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complexity

B2 noun #3,000 most common 15 min read

complexity

Top 3,000

Practice it Examples Notes & Tips complexity in 30 Seconds

Explanation complexity in your Level:

Complexity is a big word for when something has many, many parts that are joined together. Think of a very big LEGO castle. It is not just one brick; it is many bricks. Because there are so many bricks, it is not simple. It is complex. We use this word when we want to say that something is not easy to understand because it has a lot of little details. For example, a computer is complex because it has many tiny parts inside. A big city is complex because it has many streets, cars, and people all moving at the same time. At this level, you can just think of it as the opposite of 'simple.' If something is simple, it is easy. If it has complexity, you need to look at it for a long time to see how it works. You might say, 'This game has a lot of complexity,' if the rules are hard to learn because there are so many of them. It is a noun, so we use it like a thing. 'The complexity' is the name for that 'not simple' feeling.

At the A2 level, you can start using 'complexity' to describe things like hobbies, games, or basic machines. Complexity means that something is made of many parts that work together. A watch has complexity because of all the tiny gears inside. A story has complexity if there are many characters and many things happening. You can use it to explain why something takes a long time to learn. You might say, 'I like the complexity of this puzzle.' This means you like that it has many pieces and is not too easy. It is a more 'grown-up' word than just saying 'it is hard.' When you use 'complexity,' you are talking about the *way* something is made, not just how you feel about it. Remember that it is a noun. You can say 'the complexity of the task' or 'the complexity of the rules.' It helps you describe the world more clearly by showing that you see the different parts of a system.

For B1 learners, 'complexity' is a useful word for discussing more abstract topics like feelings, social issues, or work projects. It refers to the quality of being intricate or having many interconnected elements. When a situation is complex, it means you cannot just give a 'yes' or 'no' answer. For example, 'The complexity of the environmental crisis' means that many things—like pollution, weather, and money—are all mixed together. You will often hear this word in the phrase 'the complexity of...' followed by a noun. It is common in professional settings. If your boss gives you a difficult job, you might say, 'I understand the complexity of this project.' This shows you are taking the job seriously and you know it will require careful thought. You should also know the adjective form, 'complex.' While 'complex' describes the thing, 'complexity' is the name of the quality itself. Using this word correctly helps you move away from simple descriptions and start expressing more nuanced ideas about how the world functions.

At the B2 level, 'complexity' is a key term for academic and professional communication. It describes systems where the components interact in non-linear ways. You should be able to distinguish between 'complexity' and 'complication.' Complexity is often an inherent part of a system (like the complexity of a language), while a complication is an added difficulty (like a complication during a flight). At this level, you can use collocations like 'sheer complexity,' 'unnecessary complexity,' or 'reduce complexity.' You might use it to discuss literature, such as the 'complexity of a character’s motives,' or science, like the 'complexity of a chemical reaction.' It is also important to use it correctly in terms of grammar, ensuring subject-verb agreement (e.g., 'The complexity of these issues *is* significant'). By using this word, you demonstrate a sophisticated grasp of English that allows you to analyze and describe intricate systems and multi-layered problems effectively. It is a staple of B2-level essays and presentations.

For C1 learners, 'complexity' is a versatile tool for high-level analysis. You should be comfortable using it in various domains, such as 'computational complexity' in IT, 'cognitive complexity' in psychology, or 'syntactic complexity' in linguistics. At this stage, you should understand that complexity can be an emergent property—where the whole is greater than the sum of its parts. You might use the word to critique a philosophical argument or to describe the 'irreducible complexity' of biological structures. In writing, you can use 'complexity' to manage the flow of information, using nominalization to turn complex ideas into the subjects of your sentences. You should also be familiar with the plural 'complexities' to refer to the specific, multifaceted aspects of a situation, such as 'navigating the complexities of international diplomacy.' Your use of the word should reflect an appreciation for nuance and an ability to handle abstract concepts with precision. It is no longer just about something being 'hard'; it is about the intricate, systemic nature of reality.

At the C2 level, your mastery of 'complexity' should involve an understanding of its role in systems theory and philosophy. You can discuss the 'complexity-simplicity' dialectic and how systems tend toward entropy or organization. You might use the term to describe the 'layered complexity' of a postmodern novel or the 'stochastic complexity' in statistical modeling. At this level, you are expected to use the word with total precision, choosing it over synonyms like 'intricacy' or 'convolution' to convey specific academic or technical meanings. You can use it to discuss the limits of human cognition or the 'inherent complexity' of the universe itself. Your sentences might involve complex structures where 'complexity' is modified by sophisticated adjectives like 'unfathomable,' 'byzantine,' or 'multi-dimensional.' You should also be able to use the word in a self-reflexive way, perhaps discussing the 'complexity of the very language' you are using. Mastery at C2 means using 'complexity' not just to describe the world, but to engage in a deep, philosophical dialogue about the nature of systems and understanding.

Practice it Examples Notes & Tips

complexity in 30 Seconds

Complexity is the state of having many interconnected parts that make something difficult to understand or analyze.
It is a noun used to describe systems, problems, or ideas that are multifaceted and dense.
Commonly used in academic and professional settings to highlight the depth of a subject.
It contrasts with simplicity and is often confused with 'complication,' though complexity is more structural.

The term complexity refers to the state of having many different parts that are connected in a way that is difficult to understand. It is not merely a synonym for 'difficulty,' though the two are often related. While something difficult requires effort to overcome, something complex requires a deep analysis of its internal relationships. In modern discourse, complexity is a fundamental concept in fields ranging from biology and computer science to sociology and economics. When we speak of the complexity of the human brain, we are referring to the billions of neurons and trillions of synapses that interact to produce consciousness. This is a structural complexity. In contrast, when a politician speaks about the complexity of a tax code, they are often highlighting the layers of rules and exceptions that make the system hard to navigate. The word suggests a certain depth and density. It implies that there is no simple, one-size-fits-all explanation for how the subject works. Instead, one must look at the 'interweaving' of various factors. This 'interweaving' is actually found in the word's history, coming from the Latin 'complexus,' meaning 'entwined' or 'twisted together.'

Structural Complexity: Refers to the physical or organizational arrangement of components within a system, such as a circuit board or a corporate hierarchy.

The sheer complexity of the software architecture made it nearly impossible for a single developer to understand the entire system.

In everyday conversation, people use 'complexity' to justify why a problem cannot be solved quickly. It serves as a linguistic buffer against oversimplification. If someone asks, 'Why can't we just end poverty?' a responder might begin by saying, 'The complexity of global economics prevents a simple solution.' This usage acknowledges that there are multiple variables—inflation, education, geography, and politics—that all influence one another. Complexity is also a quality we admire in art and literature. A complex character in a novel is one who has conflicting motivations and a rich internal life, making them feel more 'real' to the reader. In this context, complexity is a mark of quality and depth rather than a frustration. It suggests a richness that rewards close attention and repeated study. Whether it is the complexity of a mathematical proof or the complexity of a jazz composition, the word invites us to look closer and appreciate the intricate dance of parts that form a whole.

Cognitive Complexity: The mental capacity to process multiple perspectives and multifaceted information simultaneously.

She was praised for her ability to manage the complexity of the international negotiations without losing sight of the primary goal.

Furthermore, the word is frequently used in scientific research to describe 'emergent properties.' This is the idea that a system's complexity can result in behaviors that the individual parts do not possess. For example, a single water molecule is not 'wet,' but the complexity of trillions of interacting molecules creates the property of wetness. In this scientific sense, complexity is a creative force. It is the engine of evolution and the reason why the universe is more than just a collection of hydrogen atoms. When students encounter this word in academic texts, they should be prepared for a discussion about systems, patterns, and the limits of human knowledge. To describe something as complex is to admit that it possesses a level of detail that may never be fully mapped or controlled. It is a word of humility as much as it is a word of description.

Algorithmic Complexity: A measure of the amount of resources, such as time or memory, that an algorithm takes to run as a function of the input size.

Reducing the complexity of the search algorithm improved the application's performance by forty percent.

Historians often struggle with the complexity of interpreting ancient texts without modern bias.

The complexity of the ecosystem means that removing one species can have unpredictable effects on the entire food chain.

Using 'complexity' effectively requires an understanding of its grammatical role as an abstract noun. It most commonly appears as the head of a noun phrase, often followed by the preposition 'of.' For instance, 'the complexity of the situation' or 'the complexity of the design.' This structure allows the speaker to focus on the intricate nature of a specific subject. Because it is an uncountable noun in many contexts, you will rarely see it pluralized as 'complexities' unless you are referring to multiple distinct intricate features or specific aspects of a problem. For example, 'We must consider the complexities of international law' suggests that there are several different, specific intricate points within that law. In formal writing, 'complexity' serves as a sophisticated way to introduce a nuanced discussion. Instead of saying 'This is a hard topic,' a writer might say 'The inherent complexity of this topic necessitates a multi-layered approach.'

The 'Of' Construction: The most common pattern: [Noun] + 'complexity of' + [Subject]. Example: 'The increasing complexity of modern life.'

The complexity of the legal documents required a team of specialists to decipher.

Adjectives often modify 'complexity' to specify its degree or nature. 'Sheer complexity' is a common collocation used to express that the level of intricacy is overwhelming. 'Unnecessary complexity' is used in design or bureaucracy to criticize something that is more complicated than it needs to be. 'Hidden complexity' refers to something that looks simple on the surface but contains many intricate details underneath. When you are describing a process, you might use verbs like 'add' or 'increase.' For example, 'Adding a second language to the curriculum increases the complexity of the school's schedule.' Conversely, in fields like engineering or user experience design, the goal is often to 'reduce' or 'mask' complexity for the end user. This creates a functional contrast between the internal workings of a machine and the simplicity of its interface.

Verbal Collocations: Common verbs used with complexity: handle, manage, address, unravel, simplify, or acknowledge.

Scientists are still trying to unravel the complexity of the human genome.

In academic writing, 'complexity' is often used as a measure. You might read about 'syntactic complexity' in linguistics, which refers to the use of complicated sentence structures, or 'computational complexity' in computer science. In these cases, complexity is something that can be quantified and compared. For instance, 'Sentence A has a higher level of complexity than Sentence B.' This usage is very different from the more emotional or descriptive use of the word in literature. When writing a thesis or a report, using 'complexity' allows you to avoid being overly simplistic. It shows that you recognize the various factors at play. However, be careful not to use the word as a 'filler.' If you say something is complex without explaining why, you may leave your reader confused. Always follow up a mention of complexity with an explanation of the parts that make it so.

Adjectival Modifiers: Common adjectives: overwhelming, daunting, immense, growing, inherent, and technical.

The complexity of the plot kept the audience guessing until the very end of the movie.

We must not underestimate the complexity involved in launching a new satellite.

There is a certain complexity to her paintings that requires multiple viewings to fully appreciate.

You will encounter the word 'complexity' in various professional and intellectual environments. In the tech industry, it is a daily buzzword. Software engineers discuss 'cyclomatic complexity' to measure how many paths a program's code can take. If the complexity is too high, the code is difficult to test and maintain. You'll hear developers say, 'We need to refactor this to reduce complexity.' In this world, complexity is often seen as an enemy to be defeated through better design. Similarly, in the field of project management, a 'complex project' is one with many stakeholders, tight deadlines, and interdependent tasks. A project manager might say, 'Given the complexity of this rollout, we need a more detailed risk assessment.' Here, the word signals a need for caution and thorough planning. It's a way of saying, 'This isn't a simple task, so don't expect it to be easy.'

In Science & Medicine: Used to describe biological systems, genetic interactions, and the behavior of diseases.

The complexity of the neural network allows for deep learning and pattern recognition.

In the news and political commentary, 'complexity' is used to describe international relations, economic crises, and social issues. When a journalist says, 'The complexity of the conflict in the Middle East defies simple explanation,' they are warning the audience against taking sides too quickly or believing in easy solutions. It is a word that demands intellectual patience. You will also hear it in the world of finance. Financial advisors might talk about the 'complexity of the derivatives market' or the 'complexity of tax-advantaged accounts.' In these cases, complexity is often a barrier to entry for the average person, necessitating the help of an expert. The word here carries a sense of exclusivity and technical depth. If something is complex, it belongs to the realm of the specialist.

In Art & Music: Used to describe the layers of meaning in a poem or the intricate harmonies in a symphony.

Critics marveled at the complexity of the novel's structure, which jumped between three different centuries.

In educational settings, teachers use the word to describe the level of a task. A 'task of high complexity' requires students to evaluate, synthesize, and create, rather than just memorize and repeat. If a student's essay is described as having 'conceptual complexity,' it means they have explored the topic deeply and considered various nuances. Finally, in the culinary world, you might hear a food critic talk about the 'complexity of flavors' in a dish. This means the dish has many different tastes—sweet, salty, sour, bitter, umami—that are balanced perfectly. Instead of one dominant flavor, there is a sophisticated blend. In this context, complexity is a high compliment, suggesting a chef's mastery of their craft. From the lab to the kitchen, complexity is the word we use when the world shows us its many-sided nature.

In Law & Regulation: Used to describe the dense web of rules that govern modern societies and corporations.

The complexity of the environmental regulations made it difficult for the small business to stay compliant.

The complexity of the problem was such that no single expert could solve it alone.

There is an inherent complexity in human relationships that can never be fully captured by psychology.

One of the most frequent errors learners make is confusing 'complexity' with 'complication.' While they are related, their connotations are quite different. Complexity is often a natural or necessary state. For example, the complexity of a diamond's structure is what makes it beautiful and strong. A complication, however, is almost always something negative—an extra problem that makes a situation worse. If you are having surgery and a 'complication' arises, it’s bad news. If you are studying the 'complexity' of the human body, it’s just a fact of biology. Using 'complication' when you mean 'complexity' can make you sound like you are complaining about something that is actually just detailed or sophisticated. Another common mistake is using 'complexity' as an adjective. You cannot say 'This is a complexity problem.' You must say 'This is a complex problem' or 'The complexity of this problem is high.'

Complexity vs. Complication: Complexity = Many parts (Neutral/Positive). Complication = A problem that makes things harder (Negative).

Incorrect: The complication of the machine was impressive. (Unless the machine is broken, use 'complexity').

Another error involves subject-verb agreement when 'complexity' is the head of a long noun phrase. For example: 'The complexity of the various rules and regulations is overwhelming.' Many people see the plural 'regulations' and incorrectly use 'are.' Remember that the subject is 'complexity,' which is singular. Similarly, learners sometimes over-pluralize the word. While 'complexities' is a valid word, it should only be used when referring to specific, individual intricate details. If you are talking about the general state of being complex, stick to the singular 'complexity.' For instance, 'I am overwhelmed by the complexity (not complexities) of the task.' If you want to talk about the different parts that make it hard, you could say 'I am struggling with the complexities of the various software modules.'

Agreement Error: Wrong: The complexity of the systems are high. Right: The complexity of the systems IS high.

She explained the complexities of the tax system in a way we could all understand.

Finally, watch out for 'complexity' vs 'difficultness' or 'hardness.' While 'difficultness' is a word, it is rarely used in natural English. 'Complexity' is much more common in formal settings to describe something that is hard because of its structure. Using 'hardness' to describe a math problem sounds childish; using 'complexity' sounds professional. However, don't use 'complexity' if something is simply hard to do physically. You wouldn't say 'The complexity of lifting this box is high.' That is just 'difficulty' or 'weight.' Complexity requires parts and relationships. If there are no parts to analyze, 'complexity' is the wrong word. Understanding these nuances will help you use the word with precision and authority in your writing and speaking.

Category Error: Don't use complexity for physical effort. Use it for systems, ideas, and structures.

The complexity of the puzzle kept me busy for hours, but it wasn't frustrating.

Adding more features to the app will only increase its complexity and confuse the users.

He was fascinated by the complexity of the clock's internal gears.

When you want to avoid repeating 'complexity,' several alternatives offer slightly different shades of meaning. 'Intricacy' is perhaps the closest synonym, but it often carries a more positive, aesthetic connotation. We talk about the 'intricacy of a spider's web' or the 'intricacy of lace.' It suggests a delicate and beautiful kind of complexity. If you are describing something that is complex in a way that is confusing or unnecessarily winding, 'convolution' is a better choice. For example, 'The convolution of the plot made it hard to follow.' This implies that the complexity is a flaw. 'Sophistication' is another related term, usually applied to technology, methods, or people. A 'sophisticated' system is complex, but in a way that is advanced and highly developed. It's a term of praise. Using 'sophistication' instead of 'complexity' shifts the focus from the number of parts to the quality of the design.

Complexity vs. Intricacy: Complexity is systemic and functional; Intricacy is detailed and often decorative.

The intricacy of the wood carving was visible in every tiny leaf and flower.

In more technical or academic settings, words like 'multifacetedness' or 'elaborateness' might be used. 'Multifacetedness' emphasizes that a subject has many different 'faces' or aspects to consider. It’s often used in psychology or social sciences (e.g., 'the multifacetedness of human identity'). 'Elaborateness' suggests that something has been worked on with great detail (e.g., 'the elaborateness of the ritual'). If the complexity is specifically about things being mixed together, 'entanglement' might be appropriate, particularly in physics or emotional contexts. For instance, 'the entanglement of their financial interests' suggests a complexity that is hard to separate. On the other end of the spectrum, if you want to describe the lack of complexity, 'simplicity' is the direct antonym, but 'straightforwardness' is also useful for describing processes that are easy to follow.

Complexity vs. Sophistication: Complexity is the 'what' (many parts); Sophistication is the 'how well' (advanced level).

The sophistication of modern cyber-attacks requires equally advanced defense systems.

When comparing 'complexity' to 'diversity,' remember that diversity refers to the variety of different types of things, while complexity refers to how they interact. A forest with many types of trees has high diversity; the way those trees, fungi, and animals interact to survive is the complexity of the ecosystem. You can have high diversity with low complexity (e.g., a collection of many different stamps) or high complexity with low diversity (e.g., a complex machine made of only three types of parts). Understanding these distinctions allows for much more precise communication. In a business report, choosing 'operational complexity' over 'operational difficulty' shows that you understand the system is the problem, not necessarily the people working within it. Choosing the right synonym depends entirely on whether you want to praise the detail, criticize the confusion, or simply describe the structure.

Complexity vs. Convolution: Complexity can be elegant; Convolution is usually messy and hard to follow.

The convolution of the legal argument made it difficult for the jury to follow the logic.

I was struck by the elaborateness of the stage costumes.

The multifacetedness of the problem means we need experts from several different fields.

How Formal Is It?

Formal

Neutral

Informal

Child friendly

Slang

Fun Fact

The root 'plectere' is also the source of the words 'ply', 'fold', and 'simple' (meaning 'one-fold'). So, 'complexity' literally means 'having many folds or weaves together'.

Pronunciation Guide

UK /kəmˈplek.sə.ti/

US /kəmˈplek.sə.t̬i/

Second syllable: com-PLEX-i-ty

Rhymes With

perplexity convexity flexity annexity reflexity advextity circumflexity indexity

Common Errors

Stressing the first syllable (COM-plex-i-ty).
Pronouncing the 'x' too softly.
Adding an extra syllable (com-plex-i-ci-ty).
Changing the 'e' sound in 'plex' to 'i'.
Mumbling the final 'ty' sound.

Difficulty Rating

Reading 7/5

The word itself is common, but the contexts (science, law, tech) can be difficult.

Writing 6/5

Requires careful subject-verb agreement and knowledge of collocations.

Speaking 5/5

The pronunciation is rhythmic but requires clear syllable stress.

Listening 4/5

Easily recognizable in formal speech and documentaries.

What to Learn Next

Prerequisites

simple part hard system many

Learn Next

intricacy nuance emergence interdependent multifaceted

Advanced

entropy stochastic convolution algorithm holistic

Grammar to Know

Nominalization

Changing 'The problem is complex' to 'The complexity of the problem' allows it to be the subject.

Subject-Verb Agreement

The complexity of the systems IS (not are) rising.

Uncountable vs Countable

Use 'complexity' for the state, 'complexities' for specific details.

Adjective-Noun Collocation

Use 'great' or 'high' with complexity, not 'very'.

Prepositional Phrases

Always use 'of' after complexity: 'The complexity of...'

Examples by Level

The complexity of the toy was a surprise.

La complexité du jouet était une surprise.

Noun phrase: 'The complexity of [noun]'

I don't like the complexity of this game.

Je n'aime pas la complexité de ce jeu.

Object of the verb 'like'.

The complexity of the city is big.

La complexité de la ville est grande.

Subject of the sentence.

Can you explain the complexity?

Peux-tu expliquer la complexité ?

Direct object.

The complexity makes it hard.

La complexité le rend difficile.

Subject + verb + object.

Look at the complexity of the flower.

Regarde la complexité de la fleur.

Imperative sentence.

The complexity of the map is high.

La complexité de la carte est élevée.

Adjective 'high' modifying the state.

He likes the complexity of LEGO.

Il aime la complexité des LEGO.

Proper noun 'LEGO' in the phrase.

The complexity of the machine was amazing.

La complexité de la machine était incroyable.

Past tense 'was'.

She understood the complexity of the problem.

Elle a compris la complexité du problème.

Verb 'understand' with a noun phrase.

The complexity of the story was too much for me.

La complexité de l'histoire était trop pour moi.

Phrase 'too much for [someone]'.

We need to reduce the complexity of the rules.

Nous devons réduire la complexité des règles.

Infinitive 'to reduce'.

The complexity of the drawing is beautiful.

La complexité du dessin est belle.

Adjective 'beautiful' describing the noun.

He was confused by the complexity of the directions.

Il était confus par la complexité des directions.

Passive voice: 'confused by'.

The complexity of the task grew every day.

La complexité de la tâche augmentait chaque jour.

Verb 'grow' used metaphorically.

I appreciate the complexity of your work.

J'apprécie la complexité de votre travail.

Polite expression.

The complexity of modern technology is increasing rapidly.

La complexité de la technologie moderne augmente rapidement.

Present continuous tense.

They discussed the complexity of the new tax laws.

Ils ont discuté de la complexité des nouvelles lois fiscales.

Verb 'discuss' (no preposition needed in English).

The complexity of the human brain is still a mystery.

La complexité du cerveau humain est encore un mystère.

Noun phrase as subject.

The sheer complexity of the project was daunting.

La complexité pure du projet était intimidante.

Collocation: 'sheer complexity'.

You must account for the complexity of the situation.

Vous devez tenir compte de la complexité de la situation.

Phrasal verb 'account for'.

The complexity of the language makes it hard to learn.

La complexité de la langue la rend difficile à apprendre.

Causative structure: 'makes it [adjective]'.

We were surprised by the complexity of her emotions.

Nous avons été surpris par la complexité de ses émotions.

Prepositional phrase 'by the complexity of'.

The complexity of the ecosystem must be protected.

La complexité de l'écosystème doit être protégée.

Passive modal 'must be protected'.

The complexity of the legal system can be overwhelming for laypeople.

La complexité du système juridique peut être accablante pour les profanes.

Modal 'can be'.

The software update aims to reduce the complexity of the user interface.

La mise à jour du logiciel vise à réduire la complexité de l'interface utilisateur.

Infinitive of purpose: 'to reduce'.

The complexities of international trade are often misunderstood.

Les complexités du commerce international sont souvent mal comprises.

Plural 'complexities' used for specific aspects.

There is an inherent complexity in trying to predict the weather.

Il y a une complexité inhérente à essayer de prédire la météo.

Adjective 'inherent' modifying the noun.

The complexity of the plot kept the readers engaged until the final page.

La complexité de l'intrigue a maintenu l'engagement des lecteurs jusqu'à la dernière page.

Verb 'keep' + object + adjective.

Historians often debate the complexity of the causes of the war.

Les historiens débattent souvent de la complexité des causes de la guerre.

Noun phrase as object of 'debate'.

The complexity of the data required advanced statistical analysis.

La complexité des données a nécessité une analyse statistique avancée.

Past tense 'required'.

Managing the complexity of a global supply chain is a massive challenge.

Gérer la complexité d'une chaîne d'approvisionnement mondiale est un défi massif.

Gerund 'Managing' as the subject.

The irreducible complexity of certain biological structures is a topic of much debate.

La complexité irréductible de certaines structures biologiques est un sujet de grand débat.

Adjective 'irreducible' (C1 level vocabulary).

Her thesis explores the syntactic complexity of bilingual children's speech.

Sa thèse explore la complexité syntaxique du discours des enfants bilingues.

Specific academic term: 'syntactic complexity'.

The complexity of the algorithm determines the efficiency of the search engine.

La complexité de l'algorithme détermine l'efficacité du moteur de recherche.

Subject-verb agreement: 'complexity... determines'.

The author masterfully navigates the complexities of human grief.

L'auteur navigue avec brio dans les complexités du deuil humain.

Metaphorical use of 'navigates'.

Economic models often fail to capture the full complexity of human behavior.

Les modèles économiques échouent souvent à capturer toute la complexité du comportement humain.

Infinitive 'to capture'.

The complexity of the negotiations was compounded by the presence of the media.

La complexité des négociations a été aggravée par la présence des médias.

Passive voice: 'was compounded by'.

There is a growing complexity in the way we consume digital information.

Il y a une complexité croissante dans la façon dont nous consommons l'information numérique.

Adjective 'growing' (present participle).

The complexity of his argument was lost on most of the audience.

La complexité de son argument a échappé à la plupart de l'auditoire.

Idiom: 'lost on [someone]'.

One must embrace the complexity of the world rather than seeking reductive certainties.

Il faut embrasser la complexité du monde plutôt que de chercher des certitudes réductrices.

Subjunctive-like 'must embrace' and gerund 'seeking'.

The sheer stochastic complexity of the market makes long-term forecasting nearly impossible.

La pure complexité stochastique du marché rend les prévisions à long terme presque impossibles.

Technical adjective 'stochastic'.

The novel's structural complexity mirrors the fragmented consciousness of its protagonist.

La complexité structurelle du roman reflète la conscience fragmentée de son protagoniste.

Verb 'mirrors' (academic register).

We are only beginning to fathom the complexity of the quantum realm.

Nous commençons seulement à sonder la complexité du royaume quantique.

Verb 'fathom' (C2 level vocabulary).

The bureaucratic complexity of the European Union is a frequent target of criticism.

La complexité bureaucratique de l'Union européenne est une cible fréquente de critiques.

Noun phrase as subject.

The complexity of the ethical dilemma left the committee in a state of paralysis.

La complexité du dilemme éthique a laissé le comité dans un état de paralysie.

Metaphorical 'state of paralysis'.

The music is characterized by a high degree of rhythmic and harmonic complexity.

La musique est caractérisée par un degré élevé de complexité rythmique et harmonique.

Passive voice: 'is characterized by'.

The complexity of the interplay between nature and nurture cannot be overstated.

La complexité de l'interaction entre l'inné et l'acquis ne peut être surestimée.

Set phrase: 'cannot be overstated'.

Synonyms

intricacy complication sophistication convolution elaborateness multifacetedness

Antonyms

simplicity clarity straightforwardness

Common Collocations

reduce complexity

sheer complexity

unnecessary complexity

manage complexity

growing complexity

inherent complexity

level of complexity

handle complexity

technical complexity

layers of complexity

Common Phrases

the complexity of the situation

— Used to explain that a problem is not simple and has many factors.

He didn't realize the complexity of the situation until it was too late.

a high degree of complexity

— A formal way to say something is very complex.

The engine was built with a high degree of complexity.

add a layer of complexity

— To make something more complicated by adding a new factor.

The language barrier added a layer of complexity to the talks.

navigating the complexities

— To deal with the various difficult parts of something.

She is skilled at navigating the complexities of corporate law.

embrace complexity

— To accept and work with the fact that something is complex.

Designers must learn to embrace complexity without confusing the user.

beyond the complexity

— To look past the difficult parts to see the core truth.

Beyond the complexity of the math, the concept is simple.

unravel the complexity

— To explain or understand something that is very complex.

Scientists are working to unravel the complexity of the brain.

scale of complexity

— The range from simple to very complex.

This project is at the top of the scale of complexity.

hidden complexity

— Something that looks simple but is actually very complex.

The clean interface hides the hidden complexity of the software.

stunning complexity

— Complexity that is impressive or beautiful.

The telescope revealed the stunning complexity of the nebula.

Often Confused With

complexity vs complication

A complication is a problem that makes things harder; complexity is just the state of having many parts.

complexity vs difficulty

Difficulty is how hard something feels; complexity is how many parts something has.

complexity vs intricacy

Intricacy is often used for small, beautiful details; complexity is for larger systems.

Idioms & Expressions

"a tangled web"

— A very complex or confusing situation, often involving lies.

They found themselves in a tangled web of deceit.

informal/literary

"not rocket science"

— Used to say that something is NOT complex.

Cooking pasta is not rocket science.

informal

"the devil is in the detail"

— Small things in a complex plan can cause big problems.

The plan looks good, but the devil is in the detail.

neutral

"a can of worms"

— A complex situation that causes more problems when you start to deal with it.

Opening that investigation will be a real can of worms.

informal

"many moving parts"

— Used to describe a complex project or organization.

This deal has many moving parts that we need to coordinate.

neutral/business

"a labyrinth of..."

— A very complex and confusing system (like a maze).

He got lost in a labyrinth of bureaucracy.

literary/formal

"wheels within wheels"

— Used to describe a situation with many hidden complexities.

In politics, there are often wheels within wheels.

literary

"a minefield of..."

— A complex situation where it is easy to make a mistake.

The new regulations are a minefield of potential errors.

informal/neutral

"too many cooks spoil the broth"

— When too many people add complexity to a task, it fails.

We don't need five managers; too many cooks spoil the broth.

informal

"clear as mud"

— Used sarcastically to say something is very complex and confusing.

His explanation of the new law was clear as mud.

informal

Easily Confused

complexity vs Complex

It is the adjective form.

Complex describes the thing; complexity is the noun for the quality.

The system is complex. Its complexity is high.

complexity vs Complicated

Often used as a synonym.

Complicated often implies that something is difficult to deal with or has gone wrong.

The situation became complicated after he lied.

complexity vs Complexion

Similar spelling.

Complexion refers to the skin on a person's face.

She has a very clear complexion.

complexity vs Complicity

Very similar spelling.

Complicity means being involved in a crime or wrongdoing.

He was accused of complicity in the theft.

complexity vs Simplicity

It's the antonym.

Simplicity is the lack of complexity.

I love the simplicity of this design.

Sentence Patterns

The complexity is [adjective].

The complexity is high.

I like the complexity of [noun].

I like the complexity of this puzzle.

Due to the complexity of [noun], [result].

Due to the complexity of the rules, I lost the game.

[Verb] the complexity of [noun].

We need to reduce the complexity of the system.

The [adjective] complexity of [noun] [verb].

The inherent complexity of the brain fascinates scientists.

Navigating the complexities of [noun].

Navigating the complexities of international law is difficult.

[Gerund] the complexity of [noun] requires [noun].

Unraveling the complexity of the universe requires patience.

The complexity is compounded by [noun].

The complexity is compounded by the lack of data.

Word Family

Nouns

Verbs

Adjectives

How to Use It

frequency

Common in academic, technical, and professional English. Rare in very basic daily speech.

Common Mistakes

The complexity of the tasks are too high. → The complexity of the tasks is too high.
The subject is 'complexity' (singular), not 'tasks'.
This is a very complexity problem. → This is a very complex problem.
Complexity is a noun; complex is the adjective needed here.
I don't like the complication of the rules. → I don't like the complexity of the rules.
Rules are complex by design; 'complication' implies something went wrong.
He has a lot of complicity in his life. → He has a lot of complexity in his life.
Complicity means involvement in a crime. Complexity means having many parts.
We need to simplify the complexities. → We need to reduce the complexity.
While 'complexities' is okay, 'reduce the complexity' is the more standard professional collocation.

Tips

Watch the Verb

Always use a singular verb with 'complexity,' even if it is followed by plural words. 'The complexity of the machines IS...' not 'ARE.'

Pair with Adjectives

Use 'sheer,' 'inherent,' or 'unnecessary' to give the word more flavor in your writing.

Use for Nuance

Use the word when you want to show that you are not oversimplifying a difficult topic.

Nominalization Power

Use 'The complexity of the issue' as a subject to make your sentences sound more professional than 'The issue is complex.'

Identify the Domain

When you hear 'complexity,' identify if the speaker is talking about science, tech, or emotions to understand the specific meaning.

The LEGO Rule

Remember: One brick is simple; a castle is complexity. The word is about the 'castle' of the idea.

Avoid Clichés

Try not to use 'complexity' just to sound smart. Use it only when there are actually many parts to discuss.

Measure It

In essays, talk about 'levels' or 'degrees' of complexity to show you are thinking analytically.

Problem vs System

In business, use 'complexity' to describe the system and 'complication' to describe a specific error.

Plural Use

Only use 'complexities' when you can list the specific parts. Otherwise, use the singular.

Memorize It

Mnemonic

Think of a 'complex' apartment building: it has many 'PLEX'es (units) all tied together in one big building. Complexity is the state of having all those parts.

Visual Association

Imagine a giant ball of colorful yarn that has been tangled together. Every color is a different part of the system, and the tangling is the complexity.

Word Web

Systems Intricacy Patterns Interconnected Analysis Detail Multifaceted Sophistication

Challenge

Write a paragraph describing your favorite video game or movie, using the word 'complexity' at least three times to describe the story, the characters, and the mechanics.

Word Origin

From the Middle French 'complexité', which comes from the Late Latin 'complexitas'. This in turn stems from 'complexus', the past participle of the Latin verb 'complecti'.

Original meaning: 'Complecti' means 'to entwine', 'to encircle', or 'to embrace'. It is formed from 'com-' (together) and 'plectere' (to weave or braid).

Indo-European (Italic/Latin branch).

Cultural Context

No specific sensitivities, but avoid using 'complexity' to dismiss someone's concerns as too difficult to understand.

In English-speaking business culture, 'reducing complexity' is a common goal for CEOs and managers.

Complexity Science (Santa Fe Institute) The book 'Complexity' by Mitchell Waldrop The 'Irreducible Complexity' argument in biology

Practice in Real Life

Real-World Contexts

Software Engineering

time complexity
space complexity
code complexity
manage technical complexity

Biology & Ecology

biological complexity
ecosystem complexity
genetic complexity
structural complexity

Business & Management

operational complexity
market complexity
reduce organizational complexity
navigating business complexities

Literature & Art

narrative complexity
character complexity
harmonic complexity
visual complexity

Politics & Law

legal complexity
bureaucratic complexity
geopolitical complexity
regulatory complexity

Conversation Starters

"How do you deal with the complexity of modern life and stay organized?"

"Do you think the complexity of technology is making us smarter or more stressed?"

"What is the most complex book you have ever read, and why was it so difficult?"

"In your job, what is the biggest source of unnecessary complexity?"

"Do you prefer simple games or games with a high level of complexity?"

Journal Prompts

Describe a time when you were overwhelmed by the complexity of a task. How did you break it down?

Reflect on the complexity of a close relationship in your life. What are the different layers involved?

Write about a scientific concept whose complexity fascinates you (e.g., space, the brain, evolution).

If you could simplify one complex part of the world (like taxes or travel), what would it be and why?

How does the complexity of your native language compare to the complexity of English?

Frequently Asked Questions

10 questions

No, complexity is often neutral or even positive. In nature, complexity allows for life and evolution. In art, it provides depth. It only becomes 'bad' when it makes a system inefficient or impossible to use.

Use 'complexities' when you are talking about several different, specific difficult parts of a situation. For example: 'The complexities of the new law include tax changes and labor rules.' Use 'complexity' for the general idea.

No, 'complexity' is a noun. You should say 'great complexity' or 'high complexity.' If you want to use 'very,' use the adjective: 'The task is very complex.'

It is a field in computer science that studies how much time or memory an algorithm needs to solve a problem as the problem gets bigger.

Yes, but it is much less common than 'complexity.' It's usually better to stick with 'complexity' in almost all situations.

It means making a company's processes, products, or rules simpler so that they are easier to manage and less expensive to run.

The 'x' sounds like 'ks.' So it is 'kuhm-PLEK-si-tee.'

Not exactly. Diversity is having many different *types* of things. Complexity is how those things *interact* with each other.

A Google search is a great example. To the user, it is a simple box and a button. Behind that box, there is a massive, complex system of algorithms and servers.

Yes, humans often feel 'complex emotions,' where they feel two different things at once, like being both happy and sad at a graduation.