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B1 adjective #25 le plus courant 14 min de lecture

unstable

Top 25

At the A1 level, 'unstable' is a word you might use to describe things you can see and touch. Imagine a chair that has one leg shorter than the others. When you sit on it, it moves. That chair is unstable. Or imagine a tall tower made of toy blocks. If it looks like it will fall over, it is unstable. It is the opposite of 'steady' or 'safe.' You use it to say that something is not strong and might break or fall down. It is a very useful word for talking about simple physical problems in your house or at school. For example, 'The table is unstable' or 'This ladder is unstable.' It helps you tell people to be careful because something might fall. At this level, you don't need to worry about the abstract meanings like 'unstable economy.' Just think about things that might fall over or break easily.

At the A2 level, you can start using 'unstable' for more than just physical objects. You might use it to talk about the weather or how someone feels. If the weather changes very quickly from sunny to rainy, you can say the weather is unstable. If a friend is very happy and then suddenly very sad, you might say their mood is unstable. It means 'likely to change' or 'not staying the same.' You can also use it for simple situations. For example, if you have a job but you might lose it tomorrow, your job situation is unstable. It is a good word to use when you want to describe a situation that makes you feel a little bit worried because you don't know what will happen next. It's more than just 'bad'; it's 'not certain.'

At the B1 level, you should be comfortable using 'unstable' in many different contexts. You can use it to describe physical objects (an unstable bridge), emotional states (an unstable personality), and social or economic situations (an unstable government). You understand that 'unstable' implies a risk of failure or collapse. For example, if a company is 'financially unstable,' it means they might go out of business soon. You can also use it to describe technical things, like an 'unstable internet connection' that keeps disconnecting. At this level, you should be able to explain *why* something is unstable. For instance, 'The building is unstable because the foundation is old.' You are moving beyond simple descriptions to explaining the cause and effect of instability in the world around you.

At the B2 level, you use 'unstable' with more precision and nuance. You understand its role in professional and academic settings. You might use it in an essay to describe a 'politically unstable region' or an 'unstable chemical isotope.' You are aware of common collocations like 'unstable equilibrium' or 'unstable environment.' You can also use it metaphorically, such as describing an 'unstable argument' that lacks logical support. At this level, you can distinguish between 'unstable' and similar words like 'volatile' or 'precarious.' You might say, 'While the market is volatile, the underlying economic structure remains stable.' This shows you understand that instability can be a temporary state or a fundamental flaw. You can also use adverbs to modify the word, like 'inherently unstable' or 'dangerously unstable.'

At the C1 level, you use 'unstable' to describe complex systems and abstract theories. You might discuss the 'unstable nature of identity' in a literature class or the 'unstable dynamics of a fluid' in a physics lecture. You recognize the word's importance in various specialized fields, from meteorology to macroeconomics. You can use the word to convey subtle meanings, such as the 'unstable peace' between two nations that are not fighting but are on the verge of conflict. Your use of the word is sophisticated, and you can use it to create specific tones in your writing, whether it's a sense of impending doom or a technical analysis of a system's failure points. You are also familiar with the noun form 'instability' and can use both interchangeably to vary your sentence structure and maintain a high level of academic or professional discourse.

At the C2 level, you have a complete mastery of 'unstable' and its many connotations. You can use it in highly specialized contexts, such as 'unstable manifolds' in mathematics or 'unstable narratives' in postmodern literary criticism. You understand the historical and etymological roots of the word and how its meaning has evolved. You can use it with extreme precision to describe the most minute fluctuations in a system or the most profound shifts in human history. Your use of 'unstable' is effortless, and you can employ it in complex metaphorical constructions. You might write about the 'unstable foundations of modern civilization' or the 'unstable interplay of light and shadow' in a piece of art. At this level, the word is a tool for deep analysis and creative expression, allowing you to capture the inherent unpredictability of existence itself.

Entraîne-toi Exemples Notes et astuces

unstable en 30 secondes

Unstable means not firmly fixed or likely to change, fail, or collapse suddenly and unpredictably in various contexts.
It can describe physical objects like shaky furniture, emotional states like mood swings, or abstract systems like economies.
The word implies a lack of balance and a high risk of danger or failure if not addressed or stabilized.
Commonly used in science, medicine, politics, and daily life to warn of unpredictability and potential negative outcomes.

The word unstable is a versatile adjective used to describe anything that lacks balance, security, or predictability. At its core, it suggests a state of being where a sudden change, failure, or collapse is not just possible but likely. Whether you are talking about a physical object that might tip over or a complex global economy that is fluctuating wildly, the essence of the word remains the same: a lack of firm footing or consistency. In everyday conversation, people use this word to warn others about potential dangers or to describe situations that feel out of control. It is a word that carries a sense of urgency and caution, often implying that intervention or careful handling is required to prevent a negative outcome.

Physical Stability: When applied to physical objects, unstable refers to things that are top-heavy, poorly supported, or placed on uneven ground. A ladder leaning against a slippery wall is unstable. A pile of books stacked haphazardly is unstable. In these cases, gravity is the primary force threatening to cause a collapse.

The old wooden bridge felt dangerously unstable as the hikers crossed the rushing river.

Emotional and Mental States: In psychology, the word describes a person whose moods or behaviors change rapidly and unpredictably. An unstable person might be happy one moment and furious the next without an obvious external cause. This usage requires sensitivity, as it often touches on mental health concerns.

Beyond the physical and personal, we often hear this word in the context of systems. An unstable government is one that might be overthrown or face a sudden change in leadership. An unstable chemical compound is one that might react violently or decompose quickly. In all these contexts, the common thread is the absence of a steady state. Scientists use the term to describe isotopes that decay over time, releasing radiation. Economists use it to describe markets where prices swing up and down with no clear trend. The word is essential for describing the precarious nature of our world, from the microscopic level of atoms to the macroscopic level of international relations.

After the sudden resignation of the prime minister, the country entered an unstable political period.

Economic Context: An unstable market is characterized by high volatility, where investors are uncertain and prices do not reflect long-term value but rather short-term panic or speculation.

The startup's financial situation remained unstable despite the recent influx of venture capital.

Understanding the word 'unstable' also means recognizing its opposites. While 'stable' implies a return to equilibrium after a disturbance, 'unstable' implies that a small disturbance will lead to a much larger change. Imagine a ball at the very top of a hill; it is in an unstable position because the slightest push will send it rolling down. This visual metaphor is helpful for understanding why we use the word for everything from weather patterns to computer software. If a program is unstable, it might crash if you perform a simple task. If the weather is unstable, a clear sky could turn into a thunderstorm in minutes. It is a word that describes the edge of chaos, the moment before something gives way.

The patient's heart rate was unstable throughout the night, requiring constant monitoring by the nursing staff.

The software update made the entire operating system unstable, causing frequent reboots.

Using the word unstable correctly requires an understanding of its grammatical role as an adjective and the specific nouns it typically modifies. Because it describes a state of being, it most frequently follows linking verbs like 'is,' 'seems,' 'became,' or 'remains.' However, it can also be used directly before a noun to provide a descriptive quality. When you use 'unstable,' you are often making a judgment about the reliability or safety of something. It is important to match the intensity of the word with the context. For instance, calling a chair 'unstable' is a simple observation, but calling a global peace treaty 'unstable' carries significant political weight.

Attributive Usage: This is when 'unstable' comes before the noun. Example: 'The unstable building was marked for demolition.' Here, the adjective directly identifies a permanent or semi-permanent characteristic of the building.

The geologist warned that the unstable cliff face could collapse at any moment during the rainstorm.

Predicative Usage: This is when 'unstable' follows a verb. Example: 'The economy is unstable.' This often describes a current state that might change, rather than an inherent quality.

When constructing sentences, think about the cause of the instability. Is it due to external forces, internal flaws, or a lack of support? This will help you choose the right surrounding words. For example, if you are talking about a person, you might say they are 'emotionally unstable' to be specific. If you are talking about a chemical, you might say it is 'chemically unstable.' The word 'unstable' often pairs with 'condition,' 'environment,' 'relationship,' and 'foundation.' These pairings, known as collocations, make your English sound more natural. For instance, 'an unstable foundation' is a common way to describe both a literal building problem and a metaphorical problem with a plan or theory.

Due to the unstable nature of the chemicals, they must be stored in a temperature-controlled environment.

Metaphorical Usage: You can use 'unstable' to describe abstract things like ideas or arguments. 'His argument was built on unstable logic' means the reasoning was weak and easily proven wrong.

The peace treaty proved to be unstable as both sides continued to argue over border rights.

Finally, consider the duration of the instability. Is it a temporary state or a permanent characteristic? This often dictates which verb you use. 'The table became unstable' suggests something happened to make it that way, like a screw coming loose. 'The table is unstable' suggests a more general state. In scientific writing, 'unstable' is often used to describe a transition state. For example, 'The intermediate molecule is highly unstable and exists for only a fraction of a second.' This precision is what makes 'unstable' such a powerful word in academic and professional English. It allows you to describe the exact point where a system is most vulnerable to change.

The internet connection was unstable during the video call, causing the image to freeze repeatedly.

Critics argued that the new law would create an unstable environment for small business owners.

The word unstable is a staple of news broadcasts, scientific journals, and professional reports. You will hear it frequently in weather forecasts when meteorologists discuss 'unstable air masses' that could lead to severe storms. In the financial world, news anchors often talk about 'unstable markets' when stock prices are dropping or swinging wildly. This word is also very common in medical dramas or real-life hospital settings, where a patient's 'unstable condition' is a cause for immediate concern. It is a word that signals a lack of safety and a need for attention, making it very common in high-stakes environments.

News and Politics: Journalists use 'unstable' to describe regions experiencing war, protests, or frequent changes in government. It conveys a sense of unpredictability and danger for the people living there.

The news report highlighted the unstable situation in the border region following the recent conflict.

Science and Technology: In chemistry and physics, 'unstable' describes atoms or molecules that are likely to change. In tech, it refers to software or hardware that crashes or fails to perform consistently.

In everyday life, you might hear this word when someone is talking about their personal life or relationships. An 'unstable relationship' is one that is full of drama, breakups, and reconciliations. You might also hear it in the context of construction or home repair. If a contractor says a wall is 'unstable,' they are telling you it is not safe and needs to be fixed. The word is also common in sports commentary, particularly when discussing a player's performance or a team's standing. If a team has an 'unstable defense,' they are prone to making mistakes and letting the other team score. It is a word that describes a lack of reliability across almost every human endeavor.

The meteorologist warned that unstable air moving from the north would bring heavy rain and hail.

Psychology and Health: Doctors and therapists use 'unstable' to describe physical vital signs or mental states that are fluctuating dangerously and need stabilization.

The therapist noted that the patient's mood had been unstable since the loss of their job.

Finally, 'unstable' is a common word in literature and film. Authors use it to describe characters who are unpredictable or environments that feel threatening. A 'mentally unstable' villain is a common trope in thrillers, used to create a sense of danger because the audience doesn't know what the character will do next. Similarly, a 'geologically unstable' setting, like a volcano about to erupt or a crumbling castle, creates external tension. The word is powerful because it taps into a fundamental human fear: the fear of the ground giving way beneath us, whether literally or figuratively. It is a word that perfectly captures the feeling of being on the brink of a major change.

The movie's plot centered around an unstable scientist whose experiments went horribly wrong.

Investors are wary of putting money into unstable emerging markets during a global recession.

While unstable is a common word, it is often misused in ways that can change the meaning of a sentence or make it sound unnatural. One of the most frequent mistakes is confusing 'unstable' with 'unsteady.' While they are similar, 'unsteady' usually refers to physical movement or a lack of rhythm (like an unsteady hand or an unsteady walk), whereas 'unstable' refers to a lack of balance or a tendency to collapse. Another common error is using 'unstable' when 'unreliable' would be more appropriate. A person who is late for meetings is 'unreliable,' but a person whose personality changes drastically is 'unstable.' Understanding these nuances is key to using the word correctly.

Unstable vs. Unsteady: 'Unsteady' is often temporary or related to movement (e.g., 'an unsteady gait'). 'Unstable' is more about the structural or fundamental lack of balance (e.g., 'an unstable foundation').

Incorrect: He has an unstable hand when he draws. (Better: unsteady)

Unstable vs. Volatile: 'Volatile' is often used for things that change rapidly and potentially violently, like chemicals or stock markets. 'Unstable' is broader and can apply to physical objects that simply might fall over.

Another mistake involves the preposition used after 'unstable.' Usually, we don't use a preposition directly after 'unstable' unless we are specifying the area of instability, such as 'unstable in its design' or 'unstable under pressure.' Some learners mistakenly say 'unstable of' or 'unstable to,' which is incorrect. Additionally, be careful with the adverb form 'unstably.' While it exists, it is much less common than the adjective. Instead of saying 'He walked unstably,' it is more natural to say 'He walked unsteadily' or 'His walk was unstable.' Precision in these small details will significantly improve your fluency and make your descriptions more accurate.

Incorrect: The table is unstable of its legs. (Correct: The table's legs are unstable / The table is unstable because of its legs.)

Overusing the Word: Sometimes people use 'unstable' when they just mean 'bad' or 'weak.' Try to reserve 'unstable' for things that are specifically at risk of falling, changing, or failing suddenly.

The bridge became unstable after the floodwaters eroded the riverbank.

Finally, remember that 'unstable' is an absolute-leaning adjective, but it can still be graded. You can say something is 'somewhat unstable' or 'extremely unstable.' However, avoid redundant phrases like 'unstable and not steady,' as 'unstable' already implies a lack of steadiness. In professional writing, being concise is better. If you say a situation is 'unstable,' you have already conveyed a lot of information. Adding more words that mean the same thing can dilute your message. Focus on describing *why* it is unstable or *what* the consequences of that instability might be to provide a clearer picture for your reader or listener.

The unstable chemical reaction produced a bright flash and a loud pop.

The political alliance was unstable from the start due to conflicting interests.

To truly master the word unstable, it is helpful to know its synonyms and how they differ in nuance. While 'unstable' is a great general-purpose word, sometimes a more specific term can make your writing more vivid or precise. For example, if you are talking about a physical object that is likely to fall, 'wobbly' or 'shaky' might be more descriptive. If you are talking about a situation that is dangerous and could change for the worse at any moment, 'precarious' is a powerful alternative. Each of these words carries a slightly different 'flavor' and is suited to different registers of English, from casual conversation to formal academic writing.

Precarious: This word implies a lack of security that is specifically dangerous. A person standing on the edge of a cliff is in a precarious position. It is more formal and intense than 'unstable.'

The mountain climber found himself in a precarious spot when the rope began to fray.

Volatile: Used for things that change suddenly and often violently. It is the best word for stock markets, chemical reactions, or explosive tempers.

Other alternatives include 'erratic,' which describes something that doesn't follow a regular pattern, and 'fickle,' which is often used for people or weather that changes their mind or state frequently. 'Insecure' is another synonym, though it is more often used for psychological feelings of doubt or physical objects that aren't locked or fastened properly. When choosing an alternative, consider the 'why' behind the instability. If it's because of a lack of pattern, use 'erratic.' If it's because of a lack of physical support, use 'unsteady.' If it's because of a high risk of danger, use 'precarious.' This level of detail will make your English much more sophisticated and effective in communicating your exact meaning.

The stock market has been incredibly volatile this week, with prices swinging by five percent daily.

Erratic: Describes behavior or movement that is not regular or certain. 'His erratic driving made the other motorists nervous.'

The patient's erratic breathing was a sign that the medication was not working as expected.

In summary, while 'unstable' is your 'go-to' word for anything that lacks balance or predictability, don't be afraid to explore these other options. 'Wavering' is great for describing someone who can't make a decision. 'Capricious' is a sophisticated word for someone who changes their mind on a whim. 'Mutable' is a more scientific or philosophical word for things that are capable of change. By building a cluster of related words around 'unstable,' you will be able to describe the world with much greater nuance and precision. Whether you are writing a lab report, a business analysis, or a personal story, having the right word for the right kind of instability is a hallmark of an advanced English speaker.

The wobbly table was easily fixed by placing a piece of folded cardboard under one leg.

The political climate remains unstable as the nation prepares for the upcoming elections.

How Formal Is It?

Formel

Neutre

Informel

Child friendly

Argot

Le savais-tu ?

The root of 'unstable' is the same as the word 'stand'. Essentially, if something is unstable, it literally 'cannot stand' on its own.

Guide de prononciation

UK /ʌnˈsteɪ.bəl/

US /ʌnˈsteɪ.bəl/

The primary stress is on the second syllable: un-STAY-ble.

Rime avec

table cable label fable able stable enable disable

Erreurs fréquentes

Pronouncing it as 'un-stable' with the stress on the first syllable.
Confusing the 'a' sound with a short 'a' as in 'apple'.
Adding an extra vowel sound between 'b' and 'l'.
Muttering the 'un' prefix so it sounds like 'in'.
Failing to aspirate the 't' sound slightly.

Niveau de difficulté

Lecture 3/5

Common in news and books, easy to recognize.

Écriture 4/5

Requires understanding of collocations and nuance.

Expression orale 3/5

Useful for describing many everyday problems.

Écoute 3/5

Frequently heard in various media contexts.

Quoi apprendre ensuite

Prérequis

stable steady change fall safe

Apprends ensuite

volatile precarious equilibrium fluctuate deteriorate

Avancé

metastable thermodynamically stochastic entropy oscillation

Grammaire à connaître

Using 'un-' as a negative prefix.

Stable -> Unstable, Happy -> Unhappy.

Adjectives following linking verbs.

The situation *is* unstable.

Adverbs modifying adjectives.

The compound is *highly* unstable.

Attributive vs. Predicative adjectives.

An unstable bridge (Attributive) vs. The bridge is unstable (Predicative).

Noun formation from adjectives using '-ity'.

Unstable -> Instability (Note the change from 'un-' to 'in-').

Exemples par niveau

The chair is unstable, so do not sit on it.

La chaise est instable, donc ne t'assieds pas dessus.

Adjective following the linking verb 'is'.

This tall toy tower is very unstable.

Cette grande tour de jouets est très instable.

Modified by the adverb 'very'.

The ladder felt unstable when I climbed it.

L'échelle semblait instable quand je suis monté dessus.

Follows the sense verb 'felt'.

Be careful, that table is unstable.

Fais attention, cette table est instable.

Used as a predicative adjective.

An unstable wall can fall down.

Un mur instable peut s'écrouler.

Used as an attributive adjective before the noun 'wall'.

The bike is unstable because the tire is flat.

Le vélo est instable parce que le pneu est à plat.

Explaining the cause with 'because'.

Is this box unstable on the shelf?

Est-ce que cette boîte est instable sur l'étagère ?

Used in a question format.

The small boat was unstable in the water.

Le petit bateau était instable dans l'eau.

Past tense 'was'.

The weather in spring is often unstable.

Le temps au printemps est souvent instable.

Describing a natural phenomenon.

He has an unstable mood today.

Il a une humeur instable aujourd'hui.

Attributive adjective modifying 'mood'.

The internet connection is unstable this morning.

La connexion internet est instable ce matin.

Describing a modern technology issue.

My job is unstable, so I am looking for a new one.

Mon travail est instable, donc j'en cherche un nouveau.

Describing a life situation.

The bridge is unstable after the big storm.

Le pont est instable après la grosse tempête.

Describing the result of an event.

She felt unstable after she heard the bad news.

Elle s'est sentie instable après avoir appris la mauvaise nouvelle.

Describing an emotional reaction.

The pile of plates looked unstable.

La pile d'assiettes semblait instable.

Using the verb 'looked' for appearance.

The political situation in that country is unstable.

La situation politique dans ce pays est instable.

Describing a social context.

The patient's condition is still unstable after the surgery.

L'état du patient est encore instable après l'opération.

Medical context usage.

An unstable economy makes it hard for people to save money.

Une économie instable rend difficile pour les gens d'épargner de l'argent.

Economic context usage.

The software is still unstable and crashes frequently.

Le logiciel est encore instable et plante fréquemment.

Technological context usage.

They have an unstable relationship and argue all the time.

Ils ont une relation instable et se disputent tout le temps.

Interpersonal context usage.

The chemicals are unstable and must be handled with care.

Les produits chimiques sont instables et doivent être manipulés avec soin.

Scientific context usage.

The building's foundation is unstable due to the earthquake.

La fondation du bâtiment est instable à cause du tremblement de terre.

Structural context usage.

His emotional state was unstable during the trial.

Son état émotionnel était instable pendant le procès.

Psychological context usage.

The new government is unstable and may not last long.

Le nouveau gouvernement est instable et pourrait ne pas durer longtemps.

Political context usage.

The isotope is highly unstable and decays within seconds.

L'isotope est hautement instable et se désintègre en quelques secondes.

Scientific/Technical usage with 'highly'.

The market remains unstable despite the government's intervention.

Le marché reste instable malgré l'intervention du gouvernement.

Using 'remains' to show persistence.

Her argument was based on unstable logic and was easily refuted.

Son argument était basé sur une logique instable et a été facilement réfuté.

Metaphorical usage for abstract concepts.

The region has been politically unstable for decades.

La région est politiquement instable depuis des décennies.

Adverbial modification 'politically unstable'.

The pilot had to abort the landing due to an unstable approach.

Le pilote a dû interrompre l'atterrissage en raison d'une approche instable.

Specific aviation terminology.

The company's financial structure is inherently unstable.

La structure financière de l'entreprise est intrinsèquement instable.

Using 'inherently' to describe a fundamental quality.

The ecosystem is unstable because of the loss of key species.

L'écosystème est instable à cause de la perte d'espèces clés.

Environmental/Ecological usage.

The peace treaty is unstable and could collapse at any moment.

Le traité de paix est instable et pourrait s'effondrer à tout moment.

Describing a precarious diplomatic situation.

The mathematical model proved to be unstable under extreme conditions.

Le modèle mathématique s'est avéré instable dans des conditions extrêmes.

Academic/Research context.

The philosopher argued that the concept of 'self' is inherently unstable.

Le philosophe a soutenu que le concept de 'soi' est intrinsèquement instable.

Philosophical/Abstract usage.

The software's unstable architecture led to numerous security vulnerabilities.

L'architecture instable du logiciel a entraîné de nombreuses vulnérabilités de sécurité.

Technical/Engineering usage.

The transition from monarchy to democracy was marked by an unstable interim period.

La transition de la monarchie à la démocratie a été marquée par une période intérimaire instable.

Historical/Political analysis.

The patient exhibited unstable hemodynamics throughout the procedure.

Le patient a présenté une hémodynamique instable tout au long de l'intervention.

Highly specialized medical terminology.

The poem explores the unstable boundary between reality and dreams.

Le poème explore la frontière instable entre la réalité et les rêves.

Literary/Artistic analysis.

The unstable equilibrium of the market was disrupted by the sudden news.

L'équilibre instable du marché a été perturbé par la nouvelle soudaine.

Economic/Scientific concept.

The researcher noted the unstable nature of the data collected in the field.

Le chercheur a noté la nature instable des données collectées sur le terrain.

Scientific methodology context.

The protagonist's psyche is depicted as an unstable landscape of trauma.

La psyché du protagoniste est dépeinte comme un paysage instable de traumatismes.

Advanced metaphorical literary usage.

The geopolitical landscape is increasingly unstable due to shifting alliances.

Le paysage géopolitique est de plus en plus instable en raison du changement des alliances.

Complex political analysis.

The composer utilized unstable harmonies to evoke a sense of existential dread.

Le compositeur a utilisé des harmonies instables pour évoquer un sentiment d'angoisse existentielle.

Musicology/Artistic theory.

The experiment failed because the catalyst was too unstable for the reaction.

L'expérience a échoué parce que le catalyseur était trop instable pour la réaction.

Advanced chemical science context.

The text's unstable narrative voice challenges the reader's perception of truth.

La voix narrative instable du texte remet en question la perception de la vérité par le lecteur.

Postmodern literary criticism.

The unstable isotopes provide a window into the early history of the solar system.

Les isotopes instables offrent une fenêtre sur l'histoire primitive du système solaire.

Astrophysics/Geochronology usage.

The architect's design was criticized for being structurally unstable in high winds.

La conception de l'architecte a été critiquée pour être structurellement instable par vents forts.

Professional architectural critique.

The treaty represents an unstable compromise that satisfies neither party.

Le traité représente un compromis instable qui ne satisfait aucune des parties.

Nuanced diplomatic description.

Collocations courantes

unstable condition

unstable economy

unstable environment

unstable isotope

unstable foundation

unstable relationship

unstable market

unstable air

unstable personality

unstable government

Phrases Courantes

dangerously unstable

emotionally unstable

politically unstable

chemically unstable

inherently unstable

highly unstable

mentally unstable

structurally unstable

financially unstable

socially unstable

Souvent confondu avec

unstable vs unsteady

Unsteady usually refers to movement or rhythm (an unsteady hand), while unstable refers to a lack of balance or structural integrity.

unstable vs unreliable

Unreliable means you cannot trust someone or something to do what is expected; unstable means something is likely to fail or change suddenly.

unstable vs volatile

Volatile is more specific to rapid, often violent changes, whereas unstable is a broader term for any lack of stability.

Expressions idiomatiques

"on shaky ground"

In a situation that is not certain or secure; likely to fail.

His argument for the new project is on shaky ground.

Informal

"walking on eggshells"

Being very careful because you are dealing with an unstable person or situation.

Everyone was walking on eggshells around the boss today.

Informal

"a house of cards"

An unstable organization or plan that will easily fail or collapse.

Their whole business plan was just a house of cards.

Informal

"on the brink"

Very close to a point of sudden change or collapse.

The two countries are on the brink of war.

Neutral

"teetering on the edge"

Being in a very unstable position where you might fall or fail.

The company is teetering on the edge of bankruptcy.

Neutral

"hanging by a thread"

In a very dangerous and unstable situation where success depends on very little.

His career was hanging by a thread after the scandal.

Informal

"built on sand"

Having a very weak or unstable foundation (metaphorical).

Their marriage was built on sand and didn't last long.

Neutral

"loose cannon"

An unstable person who is unpredictable and likely to cause damage.

The new manager is a bit of a loose cannon.

Informal

"thin ice"

In a risky or unstable situation where a mistake could be disastrous.

You are on thin ice with your constant lateness.

Informal

"rock the boat"

To do something that might upset an unstable but working situation.

Don't rock the boat while the negotiations are ongoing.

Informal

Facile à confondre

unstable vs instability

It is the noun form but starts with 'in-' instead of 'un-'.

Unstable is the adjective; instability is the noun. You cannot say 'The unstable of the bridge.'

The instability of the bridge was a major concern.

unstable vs unsteady

Both describe a lack of firmness.

Use unsteady for things that shake or move. Use unstable for things that might fall over or collapse.

He took a few unsteady steps before sitting down.

unstable vs precarious

Both mean likely to fall.

Precarious is more formal and emphasizes the danger of the situation.

The vase was in a precarious position on the edge of the mantle.

unstable vs volatile

Both describe things that change.

Volatile implies the change is quick and potentially explosive. Unstable is more general.

The situation in the city is volatile and could turn violent.

unstable vs fickle

Both describe things that change frequently.

Fickle is usually used for people's interests or the weather. Unstable is used for structures and systems.

Fashion is a fickle industry.

Structures de phrases

The [Noun] is unstable.

The table is unstable.

The [Noun] feels unstable.

The ladder feels unstable.

An unstable [Noun] can [Verb].

An unstable building can collapse.

The [Noun] remains [Adverb] unstable.

The market remains highly unstable.

Due to the unstable nature of [Noun], [Result].

Due to the unstable nature of the chemicals, they must be cooled.

The [Noun] is characterized by an unstable [Noun].

The era was characterized by an unstable political climate.

It is [Adjective] to [Verb] on an unstable [Noun].

It is dangerous to stand on an unstable chair.

Despite [Noun], the [Noun] is still unstable.

Despite the repair, the bridge is still unstable.

Famille de mots

Noms

Verbes

Adjectifs

Apparenté

Comment l'utiliser

frequency

Common in both spoken and written English, especially in professional contexts.

Erreurs courantes

The table is unstably. → The table is unstable.
You need an adjective (unstable) to describe the noun (table) after the verb 'is'. 'Unstably' is an adverb.
The bridge has a lot of unstability. → The bridge has a lot of instability.
The noun form of 'unstable' is 'instability'. 'Unstability' is not a word in standard English.
He has an unstable hand when he writes. → He has an unsteady hand when he writes.
For small, physical movements like shaking, 'unsteady' is more natural than 'unstable'.
The country is unstable of its government. → The country's government is unstable.
Don't use 'of' after 'unstable'. Instead, make the thing that is unstable the subject of the sentence.
She is an unstable person because she is late. → She is an unreliable person because she is late.
'Unstable' refers to mood or mental state; 'unreliable' refers to someone who doesn't do what they say they will.

Astuces

Choose the right context

Use 'unstable' for structures, systems, and emotions. Use 'wobbly' for small furniture and 'shaky' for hands or voices.

Noun form

Remember that the noun is 'instability'. Example: 'The instability of the market is worrying investors.' Don't say 'unstability'.

Use adverbs

Make your writing more precise by adding adverbs like 'politically', 'financially', or 'chemically' before 'unstable'.

Stress the second syllable

The word is pronounced un-STAY-ble. Putting the stress on the wrong part can make it hard for native speakers to understand you.

Show, don't just tell

Instead of just saying a chair is unstable, describe how it 'creaks and tilts' when someone sits on it. This makes your writing more vivid.

Warning others

In an emergency, 'It's unstable!' is a quick and effective way to tell someone to stay away from a dangerous object or area.

Context clues

If you hear 'unstable' in a hospital, it's about health. If you hear it on the news, it's likely about politics or the economy.

The Table Trick

The word 'table' is inside 'unstable'. Imagine a table with three legs; it's unstable. This will help you remember the meaning and spelling.

Be careful with people

Avoid calling a person 'unstable' directly to their face or in a casual way, as it can be very offensive and hurtful.

Scientific precision

In science papers, use 'unstable' to describe isotopes or compounds that decay. It is a precise term with a specific meaning.

Mémorise-le

Moyen mnémotechnique

Think of an UN-STABLE TABLE. If a table is UNSTABLE, it will wobble and fall. The word 'table' is even hidden inside 'unstable'!

Association visuelle

Imagine a tall tower of cards on a windy day. The tower is shaking and about to fall. This is the visual definition of unstable.

Word Web

Shaky Wobbly Dangerous Changeable Weak Unpredictable Volatile Precarious

Défi

Try to use the word 'unstable' three times today: once for a physical object, once for a feeling, and once for a situation in the news.

Origine du mot

The word comes from the Middle English 'unstable', which was formed by adding the prefix 'un-' (meaning 'not') to the word 'stable'. 'Stable' itself comes from the Old French 'estable', which originates from the Latin 'stabilis', meaning 'standing firm' or 'steadfast'.

Sens originel : Not standing firm; not steadfast; prone to change or move.

Indo-European (Latin branch)

Contexte culturel

Be cautious when using 'unstable' to describe people, as it can be stigmatizing in the context of mental health.

In the UK and US, 'unstable' is frequently heard in news reports about the economy and foreign policy.

The term 'unstable equilibrium' is a key concept in John Nash's game theory. In the movie 'A Streetcar Named Desire', the character Blanche DuBois is often described as mentally unstable. The 'Unstable' expansion in the card game Magic: The Gathering uses the word to mean wacky and unpredictable.

Pratique dans la vie réelle

Contextes réels

Physical Objects

unstable chair
unstable ladder
unstable shelf
unstable pile

Economics

unstable market
unstable currency
unstable prices
unstable growth

Psychology

unstable mood
unstable emotions
unstable behavior
unstable personality

Science

unstable isotope
unstable compound
unstable reaction
unstable state

Politics

unstable government
unstable region
unstable alliance
unstable peace

Amorces de conversation

"Have you ever tried to fix an unstable piece of furniture?"

"Do you think the current global economy is stable or unstable?"

"How do you deal with an unstable internet connection during a meeting?"

"What makes a political situation become unstable in your opinion?"

"Is the weather in your city usually stable or unstable during the spring?"

Sujets d'écriture

Describe a time when you felt emotionally unstable and what helped you feel better.

Write about a physical object you own that is unstable and why you haven't fixed it yet.

Discuss an unstable situation in the news and how it might affect the rest of the world.

Reflect on a relationship that was unstable. What were the signs of instability?

Imagine a world where everything was unstable. What would a typical day look like?

Questions fréquentes

10 questions

Yes, but be careful. Describing someone as 'mentally unstable' or 'emotionally unstable' is a serious statement and can be seen as insensitive. It is often better to describe their behavior, like saying they have 'mood swings' or 'unpredictable reactions'.

'Shaky' is more informal and usually describes a physical vibration or trembling. 'Unstable' is more formal and describes a structural or fundamental lack of balance. For example, a person's voice might be shaky, but a building's foundation is unstable.

In most contexts, yes, because it implies a risk of failure. However, in some scientific fields, an 'unstable' state is a necessary part of a process, such as a chemical reaction that leads to a new, stable product.

This is due to the Latin roots of the word. Many English words follow this pattern where the adjective uses 'un-' (from Germanic roots) and the noun uses 'in-' (from Latin roots), though both mean 'not'.

Yes, 'unstable' is a gradable adjective. You can use modifiers like 'very', 'highly', 'extremely', or 'slightly' to show the degree of instability.

In science, an unstable isotope is an atom that has too much energy or an unbalanced number of particles in its nucleus. This causes it to decay and release radiation until it becomes stable.

To fix something unstable, you usually need to 'stabilize' it. This might involve adding support, fixing the foundation, or changing the conditions (like temperature or pressure) that are causing the instability.

Yes, this is a very common modern usage. An unstable internet connection is one that disconnects frequently or has a speed that changes a lot, making it hard to use for things like video calls.

Yes, it can describe a player's performance if they are good one day and bad the next. It can also describe a team's defense if they are prone to making mistakes.

This is a state where an object is balanced, but even a tiny push will cause it to move away from that balance and not return. A pencil balanced on its tip is in unstable equilibrium.