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B2 noun #7,000 most common 8 min read

逸脱

itsudatsu Top 7,000

Practice it Examples Notes & Tips 逸脱 in 30 Seconds

Explanation 逸脱 in your Level:

At the A1 level, the word '逸脱' (itsudatsu) is quite advanced. You don't need to use it yourself yet! However, you can think of it as a very fancy way to say 'off track' or 'not following the rules.' Imagine you are drawing a line, and your pen slips—that is a tiny 'itsudatsu.' Or imagine a car that doesn't stay in the middle of the road. In your daily life, you would probably use simpler words like 'dame' (bad) or 'chigau' (different). But if you see this word in a sign or a book, just remember: it means something is moving away from where it is supposed to be. It's like a train leaving the tracks. Focus on the first character '逸' which looks a bit like a person running away, and '脱' which you might know from 'nugu' (to take off clothes). Together, they mean 'escaping' the normal way.

At the A2 level, you might start seeing '逸脱' (itsudatsu) in simple news stories or warnings. It's a formal noun. The most important thing to learn is the pattern '〜から逸脱する' (kara itsudatsu suru), which means 'to deviate from...'. For example, if you are supposed to follow a recipe but you add completely different ingredients, you are 'deviating' from the recipe. At this level, you should recognize that this word is more serious than just 'making a mistake.' It's often used when rules are involved. If a teacher says your behavior is 'itsudatsu,' they mean you are not following the school rules. It's a useful word to know for reading signs, especially in cars or factories where 'safety deviation' is a common topic. Just think of it as 'Rule + Kara + Itsudatsu' = Breaking the rule/path.

At the B1 level, you should be able to understand '逸脱' (itsudatsu) in context and perhaps use it in formal writing. This word is very common in business and technical Japanese. You will hear it when people talk about 'specifications' (shiyou) or 'plans' (keikaku). For example, if a project is costing way more than the budget, it is 'deviating from the budget.' You should also learn the phrase '常軌を逸脱する' (jouki o itsudatsu suru), which means to act in a very strange or abnormal way. This is a very common set phrase. At this stage, try to distinguish 'itsudatsu' from 'dassen' (going off-topic). Use 'itsudatsu' when you want to sound more professional or when you are talking about a serious gap between a standard and reality. It's a key word for passing the JLPT N2 level.

At the B2 level, you are expected to use '逸脱' (itsudatsu) correctly in both speaking and writing. This is the level where the word truly belongs. You should understand its sociological and technical nuances. For instance, you can use it to describe 'deviant behavior' (逸脱行動) in an essay about society. You should also be comfortable using it to describe data outliers in a technical report. A B2 learner knows that 'itsudatsu' implies a reference point—a norm, a law, or a mathematical average. You should be able to explain the difference between 'itsudatsu' (straying from a path) and 'ridatsu' (leaving a group). In a business meeting, you might say, 'We must ensure our actions do not deviate from the company's core values.' This shows a high level of vocabulary control and stylistic awareness.

At the C1 level, '逸脱' (itsudatsu) becomes a tool for nuanced philosophical and critical analysis. You will encounter it in complex literature, legal documents, and academic journals. You should understand how it is used to describe the 'transgression' of boundaries in art or literature. For example, a C1 speaker might discuss how a certain director's style 'deviates from traditional cinematic structures.' You should also be aware of its usage in formal legal contexts, such as when an official 'exceeds/deviates from their authority' (権限の逸脱). At this level, you should be able to use the word with precision, choosing it over synonyms like 'kairi' (divergence) or 'hensa' (variation) based on the specific nuance of 'crossing a line.' You can also use it metaphorically to describe a person's genius or madness that 'deviates' from human understanding.

At the C2 level, your mastery of '逸脱' (itsudatsu) is indistinguishable from a highly educated native speaker. You understand the historical etymology of the kanji and how the word's usage has evolved in modern Japanese law and sociology. You can engage in deep discussions about 'Deviance Theory' (逸脱理論) and how social structures define what is considered an 'itsudatsu.' You are sensitive to the subtle rhetorical effects of using 'itsudatsu' to frame an opponent's argument as 'off-base' or 'unreasonable.' You can use the word in its most abstract forms, such as describing the 'ontological deviation' of a character in a postmodern novel. Your usage is perfectly integrated with complex grammar, and you can effortlessly switch between 'itsudatsu' and its most formal synonyms like '乖離' or '悖る' (motoru - to go against) to achieve the exact desired tone in scholarly or high-level professional discourse.

Practice it Examples Notes & Tips

逸脱 in 30 Seconds

Itsudatsu means deviating from a norm, rule, or path. It is a formal term often used in professional, technical, or academic contexts to describe significant departures.
The word is commonly structured as 'Standard + kara itsudatsu suru'. It implies the existence of a clear boundary that has been crossed or left behind.
Common set phrases include 'jouki o itsudatsu suru' (to act abnormally) and 'shasen itsudatsu' (lane departure in driving). It is more formal than 'hazureru'.
It is distinct from 'ridatsu' (withdrawing from a group). Itsudatsu focuses on the 'straying' rather than the 'leaving,' and is often used for social deviance.

The Japanese term 逸脱 (itsudatsu) is a sophisticated noun and suru-verb that describes the act of straying, deviating, or wandering away from a prescribed course, established norm, or specific standard. While it can occasionally refer to physical movement, such as a vehicle drifting out of its lane, its primary usage in modern Japanese is abstract and intellectual. It is the go-to word when discussing actions that violate social expectations, technical specifications that fall outside of tolerance ranges, or logical arguments that lose their connection to the original premise. Understanding this word requires grasping the nuance of 'boundary.' To use itsudatsu, there must first be a clear line, rule, or path that is being crossed or left behind.

Sociological Deviation: In social sciences, it refers to 'deviance'—behavior that does not conform to social norms. This ranges from minor social faux pas to criminal acts that break the fundamental rules of society.
Technical Discrepancy: In engineering or data analysis, it refers to values that fall outside the expected parameters or specifications (spec deviation). It is critical in quality control environments.
Logical Drift: When a conversation or a project moves away from its original goal or topic, Japanese speakers say it has 'deviated' from the purpose.

彼の行動は社会的な常識から大きく逸脱している。 (His behavior deviates greatly from social common sense.)

The word is composed of two kanji: 逸 (itsu), meaning to 'evade,' 'miss,' or 'excel/surpass,' and 脱 (datsu), meaning to 'undress,' 'escape,' or 'break through.' Together, they create a powerful image of 'escaping the standard.' Unlike the word 'mistake' (machigai), which implies an error, itsudatsu implies a movement or a state of being 'outside' where one ought to be. It is frequently paired with the particle 'から' (kara) to indicate the source or standard from which the deviation is occurring.

議論が本来の目的から逸脱しないように注意してください。 (Please be careful so that the discussion does not deviate from its original purpose.)

この数値は許容範囲を逸脱しています。 (This numerical value deviates from the tolerance range.)

Grammatically, 逸脱 (itsudatsu) functions as a noun that can easily become a verb by adding 'する' (suru). The most common structural pattern is [Standard/Rule] + から + 逸脱する. This 'kara' (from) is essential because it defines the boundary that is being crossed. Without a reference point, the word loses its meaning. In business contexts, you will often see it modifying other nouns, such as itsudatsu-koui (deviant behavior) or itsudatsu-chi (outlier value). It is a 'hard' word (kango), meaning it carries a formal, objective weight often found in legal, medical, or technical documents.

Abstract Deviance: When talking about concepts like 'common sense' (常識), 'logic' (論理), or 'norms' (規範). Example: '常軌を逸脱する' (To deviate from the beaten path/act abnormally).
Operational Deviance: Used in manufacturing or project management. Example: 'マニュアルからの逸脱' (Deviation from the manual).

法的な枠組みから逸脱した行為は許されない。 (Actions that deviate from the legal framework are not permitted.)

One interesting aspect of itsudatsu is that it can describe both intentional and unintentional actions. If a scientist's experiment results in data that 'deviates' from the hypothesis, it is unintentional. However, if a person 'deviates' from social norms to make a political statement, it might be intentional. The word itself is neutral, though the contexts it describes are often problematic or noteworthy. In literary contexts, itsudatsu might be used to describe someone with a 'genius' that goes beyond (deviates from) the ordinary, though this is less common than the negative or technical usages.

その選手は、スポーツマンシップから逸脱した態度をとった。 (That player took an attitude that deviated from sportsmanship.)

You are most likely to encounter 逸脱 (itsudatsu) in high-level media, academic settings, and professional workplaces. It is not a word children use on the playground, nor is it common in casual 'text speak' among friends. Instead, it is the language of the 'NHK News' reporter or the 'Nikkei' business analyst. When a company is caught in a scandal involving safety standards, the news will report that they 'deviated from safety protocols.' In a university lecture on sociology, the professor will discuss 'deviance theory' (逸脱理論). In an IT company, a developer might report a 'deviation' in server performance metrics.

In the News: '政府のガイドラインからの逸脱が指摘されている。' (Deviation from government guidelines has been pointed out.)
In Business Meetings: '予算案からの大幅な逸脱は避けなければなりません。' (We must avoid significant deviations from the budget proposal.)

今回の不祥事は、企業倫理からの著しい逸脱である。 (This scandal is a remarkable deviation from corporate ethics.)

Another specific area where you will hear this word is in the context of 'lane departure' warning systems in modern cars. These systems are often called '車線逸脱警報' (shasen itsudatsu keihou). Here, the 'standard' is the white line on the road, and the 'deviation' is the car's physical movement over it. This is one of the few common physical applications of the word. Generally, if you hear itsudatsu, prepare for a serious conversation about rules, standards, or boundaries. It signals that something has gone 'off-track' and usually requires correction or explanation.

この議論は、本筋から逸脱しています。 (This argument is deviating from the main point.)

Learners of Japanese often confuse 逸脱 (itsudatsu) with several similar-sounding or similar-meaning words. The most common confusion is with 離脱 (ridatsu). While both involve 'leaving' something, ridatsu means to withdraw or secede from a group or a physical state (like 'withdrawing from a treaty' or 'leaving a battlefield'). Itsudatsu, on the other hand, means to stray from a path or standard while still being conceptually related to it. If you 'ridatsu' from a party, you physically leave. If you 'itsudatsu' from the party's rules, you stay in the party but break the rules.

Itsudatsu vs. Dassen (脱線): Dassen literally means 'derailment' (like a train). It is used for conversations that go off-topic. While itsudatsu can also be used for logical drift, dassen is much more casual and often implies a sudden, accidental jump to a completely unrelated topic.
Itsudatsu vs. Hazureru (外れる): Hazureru is a general verb for 'to be off' or 'to miss.' You can 'miss' a target (外れる). Itsudatsu is much more formal and usually refers to a sustained or significant gap between the actual and the ideal standard.

× 彼は組織から逸脱した。 (He deviated from the organization - sounds weird if you mean he quit.)
○ 彼は組織から離脱した。 (He withdrew from the organization.)

Another mistake is using itsudatsu for simple 'forgetting' or 'ignoring.' If you forget to bring your homework, that is not an itsudatsu. If you deliberately write your homework in a format that violates the school's strict academic standards, that is an itsudatsu. Always remember the 'standard' (基準) element. If there is no standard, there is no deviation. Finally, watch the particle usage. It is almost always '〜から逸脱する' and rarely '〜を逸脱する', though the latter is occasionally seen in specific literary idioms like '常軌を逸脱する'.

Depending on the level of formality and the specific context, you might want to replace 逸脱 (itsudatsu) with a synonym. In academic writing, 乖離 (kairi) is a very common alternative. Kairi means 'estrangement' or 'divergence' and is used when two things that should be the same (like 'ideals' and 'reality') have a wide gap between them. While itsudatsu focuses on the act of straying, kairi focuses on the resulting gap.

乖離 (Kairi): Focuses on the 'gap' or 'disconnect.' Example: '理想と現実の乖離' (The gap between ideal and reality).
脱線 (Dassen): Focuses on 'going off-topic' in conversation. Example: '話が脱線する' (The story goes off-track).
相違 (Soui): Focuses on 'difference' or 'discrepancy.' Example: '意見の相違' (Difference of opinion).

その計画は当初の予定から大きく乖離している。 (The plan has diverged greatly from the original schedule.)

In more casual or native Japanese (Yamato-kotoba) contexts, you might use verbs like sore-ru (逸れる - to stray) or hazure-ru (外れる - to be off). For example, '話がそれる' (the conversation strays) is a more natural way to say '議論が逸脱する' in a casual chat. However, if you are writing a thesis or a legal brief, itsudatsu remains the superior choice due to its precision and formal tone. It specifically highlights that there was a boundary and that boundary was crossed, which is a nuance that simpler words like hazureru lack.

道から逸れるのは簡単だが、戻るのは難しい。 (It is easy to stray from the path, but difficult to return.)

How Formal Is It?

Fun Fact

The '逸' character contains the 'rabbit' radical (in older forms) because rabbits are famous for their quick, zig-zagging escapes from predators.

Pronunciation Guide

UK it͡sɯᵝdat͡sɯᵝ

US it͡sɯᵝdat͡sɯᵝ

Flat pitch accent (Heiban). All syllables are roughly equal in length.

Rhymes With

Ketsudatsu (欠脱) Satsudatsu (殺伐 - partial) Datsudatsu (脱々) Butsu (物) Kutsu (靴) Hatsu (発) Mitsu (密) Jitsu (実)

Common Errors

Pronouncing 'tsu' as 'too'. It should be like the 'ts' in 'cats'.
Stressing the first syllable like English. Japanese pitch is about high/low, not volume.
Merging the two 'tsu' sounds into one long 's'.

Difficulty Rating

Reading 4/5

The kanji are N1/N2 level and require knowledge of formal vocabulary.

Writing 4/5

Writing the character '逸' correctly can be tricky for learners.

Speaking 3/5

Useful in professional settings, but rare in daily conversation.

Listening 3/5

Common in news and documentaries; easy to recognize once learned.

What to Learn Next

Prerequisites

外れる (Hazure-ru) 基準 (Kijun) 規則 (Kisoku) 脱ぐ (Nugu) 道 (Michi)

Learn Next

乖離 (Kairi) 遵守 (Junshu) 逸材 (Itsuzai) 脱線 (Dassen) 規範 (Kihan)

Advanced

悖る (Motoru) 逸失 (Isshitsu) 超越 (Chouetsu) 逸品 (Ippin) 変異 (Heni)

Grammar to Know

〜から (Kara) for Source/Origin

基準から逸脱する (Deviate from the standard).

〜を (O) with Intransitive-style Verbs for Space

常軌を逸脱する (To deviate from the path - 'o' shows the space being moved through).

〜つつある (Tsutsu-aru) for Ongoing Change

計画から逸脱しつつある (It is in the process of deviating from the plan).

〜ないように (Nai you ni) for Negative Purpose

逸脱しないように注意する (Be careful not to deviate).

Noun + の + Noun

本来の目的からの逸脱 (Deviation from the original purpose).

Examples by Level

くるまがみちからいつだつしました。

The car deviated from the road.

Uses basic 'kara' to show the starting point.

きまりからいつだつしてはいけません。

You must not deviate from the rules.

Simple 'te-wa ikemasen' prohibition.

せんからいつだつしないでかいてください。

Please write without deviating from the line.

Uses 'naide' to mean 'without doing'.

これはふつうからいつだつしています。

This is deviating from the normal.

Simple 'te-imasu' state.

いつだつはあぶないです。

Deviation is dangerous.

Using the noun as a subject.

ただしいみちからいつだつしない。

I will not stray from the correct path.

Simple negative verb form.

いつだつしたデータをみつけました。

I found the deviated data.

Noun modification with past tense verb.

ルールからのいつだつはだめです。

Deviation from the rules is no good.

Noun + kara no + Noun structure.

マニュアルから逸脱した操作はしないでください。

Please do not perform operations that deviate from the manual.

Standard polite prohibition.

予算から逸脱しないように計画を立てました。

I made a plan so as not to deviate from the budget.

Uses 'youni' to show purpose/intent.

彼の話は時々、本題から逸脱します。

His talk sometimes deviates from the main topic.

Frequency adverb 'tokidoki' used.

この製品は基準から逸脱しています。

This product deviates from the standards.

Present progressive/state 'te-imasu'.

安全基準からの逸脱は許されません。

Deviation from safety standards is not permitted.

Passive potential 'yurusaremasen'.

車線逸脱警報が鳴りました。

The lane departure warning sounded.

Compound noun phrase.

予定から逸脱した場合は、報告してください。

If you deviate from the schedule, please report it.

Conditional 'ba-ai' (in the case of).

それは一般的な考えから逸脱している。

That deviates from general thinking.

Plain form for objective statement.

議論が本来の目的から逸脱してしまった。

The discussion ended up deviating from its original purpose.

Uses 'te shimatta' to show regret or completion.

常軌を逸脱した行動は慎むべきだ。

One should refrain from actions that deviate from the beaten path.

Uses 'beki' (should) and a set idiom.

この数値は統計学的に見て、明らかに逸脱している。

Looking at it statistically, this value is clearly a deviation.

Uses 'te-mite' (looking at it from...) and 'akiraka ni'.

仕様書からの逸脱が原因で、不具合が発生した。

A defect occurred due to a deviation from the specifications.

Uses 'ga gen-in de' to show cause.

彼は社会の規範から逸脱することを恐れていない。

He is not afraid of deviating from the norms of society.

Nominalizing the verb with 'koto'.

プロジェクトが当初の計画から逸脱しつつある。

The project is starting to deviate from the original plan.

Uses 'tsutsu-aru' (in the process of).

法的な枠組みから逸脱した行為には罰則がある。

There are penalties for acts that deviate from the legal framework.

Conditional/relative clause modifying 'koui'.

その発言は、公務員の立場を逸脱している。

That statement deviates from the position of a public servant.

Direct object 'o' used with itsudatsu (less common but possible).

企業倫理から逸脱した経営は、長続きしない。

Management that deviates from corporate ethics will not last long.

Conditional/Relative clause structure.

実験データが予測値から著しく逸脱していることが判明した。

It was found that the experimental data significantly deviated from the predicted values.

Uses 'hanmei shita' (became clear) and 'jirushiku' (remarkably).

個人の自由は、他者の権利を逸脱しない範囲で認められる。

Individual freedom is recognized within a range that does not deviate from (infringe upon) the rights of others.

Complex conditional phrase 'nai han-i de'.

彼の理論は、現代科学の常識を逸脱しているように見える。

His theory seems to deviate from the common sense of modern science.

Uses 'youni mieru' (seems like).

マニュアルの逸脱が、今回の大規模な事故を招いた。

Deviation from the manual led to this large-scale accident.

Noun 'itsudatsu' as the subject.

社会学では、犯罪を「逸脱行動」の一種として分析する。

In sociology, crime is analyzed as a type of 'deviant behavior.'

Technical terminology usage.

その判決は、過去の判例から大きく逸脱するものであった。

The verdict was one that deviated significantly from past precedents.

Uses 'mono de atta' for formal emphasis.

目標から逸脱した場合は、速やかに軌道修正を行う必要がある。

If there is a deviation from the goal, it is necessary to promptly make a course correction.

Uses 'hitsuyou ga aru' (need to).

権限を逸脱した行為は、法的に無効とされる可能性がある。

Acts that exceed (deviate from) one's authority may be legally voided.

Uses 'kanousei ga aru' for legal hedging.

芸術における逸脱は、しばしば新しい表現の誕生を意味する。

Deviation in art often signifies the birth of new expressions.

Abstract philosophical subject.

彼の解釈は、著者の本来の意図から逸脱しているとの批判を受けた。

His interpretation was criticized as deviating from the author's original intention.

Uses 'to no hihan o uketa' (received criticism that...).

組織の論理が、個人の良心から逸脱していく過程を記述した。

I described the process by which the logic of the organization deviates from the individual's conscience.

Uses 'te-iku' to show a continuing process.

この論文の欠点は、論理の飛躍と前提からの逸脱にある。

The flaws of this paper lie in the leaps of logic and deviation from the premises.

Compound list of flaws.

伝統的な枠組みからの逸脱こそが、彼の創造性の源泉である。

It is precisely the deviation from traditional frameworks that is the source of his creativity.

Uses 'koso' for strong emphasis.

宗教的教義からの逸脱は、歴史的に異端として排除されてきた。

Deviations from religious dogma have historically been excluded as heresy.

Passive causative past 'sarete-kita'.

市場価格が適正水準から逸脱した場合、介入が行われる。

If market prices deviate from appropriate levels, intervention will take place.

Formal conditional 'ba-ai'.

言語の恣意性は、指示対象からの必然的な逸脱を内包している。

The arbitrariness of language inherently contains an inevitable deviation from the referent.

High-level linguistic theory terminology.

ポスト構造主義において、意味は常に中心から逸脱し続ける。

In post-structuralism, meaning constantly continues to deviate from the center.

Philosophical context with 'tsuzukeru'.

裁量権の逸脱・濫用は、行政訴訟において重要な争点となる。

The deviation or abuse of discretionary power becomes a key issue in administrative litigation.

Specific legal pairing 'itsudatsu/ran-you'.

近代合理主義からの逸脱として、シュルレアリスムを再定義する。

Redefining Surrealism as a deviation from modern rationalism.

Academic 'toshite' definition.

統計的有意差は、偶然による逸脱の可能性を排除するものではない。

Statistical significance does not exclude the possibility of deviation due to chance.

Double negative 'de-wa nai' nuance.

主体のアイデンティティは、社会的役割からの微細な逸脱の集積である。

The subject's identity is an accumulation of minute deviations from social roles.

Complex abstract definition.

憲法解釈が立憲主義の基本原則から逸脱することは許されない。

It is impermissible for constitutional interpretation to deviate from the basic principles of constitutionalism.

Nominalized clause 'koto wa' as subject.

情報理論におけるノイズは、送信情報の正確な再現からの逸脱と言える。

Noise in information theory can be called a deviation from the accurate reproduction of transmitted information.

Formal 'to ieru' (can be said).

Synonyms

偏脱脱線乖離反れ脱落

Antonyms

遵守適合

Common Collocations

常軌を逸脱する

目的から逸脱する

基準から逸脱する

規範から逸脱する

車線逸脱警報

本来の意図から逸脱する

法を逸脱する

許容範囲を逸脱する

枠組みから逸脱する

著しく逸脱する

Common Phrases

逸脱行動

— Deviant behavior. Used in sociology to describe actions against norms.

若者の逸脱行動が問題となっている。

逸脱値

— Outlier. A statistical value that is far from others.

この逸脱値は除外して計算してください。

逸脱事例

— A case of deviation. Used in reports to cite specific errors.

過去の逸脱事例を調査する。

論理の逸脱

— Logical deviation. When an argument loses its coherence.

それは明らかな論理の逸脱だ。

権限の逸脱

— Exceeding authority. Acting beyond one's legal power.

権限の逸脱は処罰の対象だ。

マニュアル逸脱

— Manual deviation. Not following instructions.

マニュアル逸脱が事故の原因です。

軌道からの逸脱

— Deviation from orbit/track. Physical or metaphorical.

人生の軌道からの逸脱。

常識の逸脱

— Deviation from common sense.

常識の逸脱を恐れてはいけない。

仕様逸脱

— Spec deviation. Failing to meet technical requirements.

仕様逸脱のため返品された。

本筋からの逸脱

— Straying from the main point.

本筋からの逸脱を修正する。

Often Confused With

逸脱 vs 離脱 (Ridatsu)

Ridatsu means leaving/withdrawing from a group. Itsudatsu means straying from a rule/path.

逸脱 vs 脱線 (Dassen)

Dassen is specifically for conversations going off-topic or trains derailing. Itsudatsu is broader and more formal.

逸脱 vs 逸失 (Isshitsu)

Isshitsu means to lose or miss (like 'lost profit'). Itsudatsu is about deviation.

Idioms & Expressions

"常軌を逸脱する"

— To act abnormally or eccentrically. To go beyond the bounds of normal behavior.

彼の芸術は常軌を逸脱しているが、素晴らしい。

Formal/Literary

"道から逸脱する"

— To stray from the moral or correct path in life.

一度道から逸脱すると、戻るのが大変だ。

General

"枠を逸脱する"

— To break out of conventional boundaries or frameworks.

彼の発想は既存の枠を逸脱している。

Formal

"法の網を逸脱する"

— To slip through or deviate from the reach of the law.

法の網を逸脱するような脱税行為。

Legal/Journalistic

"本分を逸脱する"

— To neglect or stray from one's duty or proper role.

学生の本分を逸脱した遊び。

Formal/Educational

"範疇を逸脱する"

— To fall outside a specific category or scope.

それは個人の責任の範疇を逸脱している。

Academic

"度を逸脱する"

— To exceed moderate limits; to go too far.

冗談も度を逸脱すると失礼になる。

General

"趣旨を逸脱する"

— To stray from the main purpose or spirit of an event/law.

会の趣旨を逸脱する発言は控えてください。

Formal

"原則を逸脱する"

— To deviate from fundamental principles.

民主主義の原則を逸脱する行為。

Political/Formal

"論理を逸脱する"

— To defy logic or be illogical.

その結論は論理を逸脱している。

Academic

Easily Confused

逸脱 vs 逸脱 (Itsudatsu)

Sounds similar to 'Ridatsu' and 'Dassen'.

Itsudatsu focuses on the movement away from a standard. Ridatsu is about physical or organizational exit. Dassen is about a sudden jump off the main track.

規範からの逸脱 (Deviation from norms) vs 組織からの離脱 (Withdrawal from the organization).

逸脱 vs 乖離 (Kairi)

Both mean 'divergence'.

Kairi describes the state of a large gap between two things. Itsudatsu describes the act of straying from a single standard.

理想と現実の乖離 (Gap between ideal and reality).

逸脱 vs 逸れる (Soreru)

Related verb.

Soreru is the native Japanese verb (Yamato-kotoba) and is softer. Itsudatsu is the formal Chinese-origin noun (Kango).

話が逸れる (The talk strays).

逸脱 vs 脱落 (Datsuraku)

Both start with 'escape/shed' (脱).

Datsuraku means to drop out of a race or to omit a letter. Itsudatsu is to stray from a path.

マラソンから脱落する (Drop out of the marathon).

逸脱 vs 超越 (Chouetsu)

Both mean going beyond something.

Chouetsu is positive 'transcendence'. Itsudatsu is usually a 'deviation' that implies an error or a problem.

次元を超越する (Transcend dimensions).

Sentence Patterns

[Noun]から逸脱しないでください。

ルールから逸脱しないでください。

[Noun]から逸脱してしまった。

予定から逸脱してしまった。

常軌を逸脱した[Noun]

常軌を逸脱した行動。

[Noun]からの逸脱が[Verb]。

基準からの逸脱が見つかった。

[Noun]を逸脱しない範囲で[Verb]。

権限を逸脱しない範囲で行動する。

[Noun]こそが[Noun]からの逸脱である。

それこそが伝統からの逸脱である。

[Noun]は[Noun]からの逸脱を内包する。

この行為は危険からの逸脱を内包している。

[Noun]の逸脱・濫用

裁量権の逸脱・濫用が疑われる。

Word Family

Nouns

逸脱 (Itsudatsu - Deviation)

逸脱者 (Itsudatsusha - Deviant person)

逸脱行動 (Itsudatsu koui - Deviant behavior)

Verbs

逸脱する (Itsudatsu suru - To deviate)

逸れる (Soreru - To stray)

脱する (Dassuru - To escape/get out of)

Adjectives

逸脱的 (Itsudatsuteki - Deviant/Divergent)

常軌 (Jouki - Beaten track)

規範 (Kihan - Norm)

基準 (Kijun - Standard)

乖離 (Kairi - Divergence)

脱線 (Dassen - Derailment)

How to Use It

frequency

Common in news, business, and academic contexts. Rare in daily casual speech.

Common Mistakes

Using itsudatsu for quitting a job. → 仕事から離脱する (Incorrect) -> 仕事を辞める / 組織から離脱する
Itsudatsu is about straying from a path, not quitting a position.
Using itsudatsu for a simple spelling error. → 綴りの逸脱 (Incorrect) -> 綴りの間違い
Itsudatsu is too formal and heavy for minor typos.
Saying 'itsudatsu o suru' instead of 'itsudatsu suru'. → 逸脱する
While 'o suru' is grammatically possible, 'itsudatsu suru' is the standard suru-verb form.
Confusing itsudatsu with dassen in casual chat. → 話が逸脱した (Sounds very formal) -> 話が脱線した
Dassen is the natural choice for 'going off-topic' in daily life.
Using 'itsudatsu' for positive transcendence without context. → 限界を逸脱した (Sounds like an error) -> 限界を超越した
Chouetsu is for 'surpassing' in a positive way; itsudatsu often implies 'straying' in a problematic way.

Tips

Use with 'Kara'

Always remember to define what you are deviating from using the particle 'kara'.

Learn the Idiom

Memorize '常軌を逸脱する' (acting abnormally) as a single block; it's very common.

Quality Control

In manufacturing, any deviation from the manual is an 'itsudatsu' and must be reported.

Formal Tone

Use this word in essays or reports to instantly sound more academic.

Sociology Context

If you study sociology, this is the standard word for 'deviance'.

Lane Departure

If your car beeps when you cross a line, that's a 'shasen itsudatsu' warning.

Itsudatsu vs Ridatsu

Itsudatsu = straying from a rule. Ridatsu = leaving a group. Don't mix them up!

Kanji Meaning

逸 means 'escape' and 脱 means 'shed'. Think of escaping the shed rules!

Objective Usage

It sounds objective and clinical, making it great for neutral reporting.

Pair with Correction

When you find an 'itsudatsu', you usually follow up with 'kido shuusei' (course correction).

Memorize It

Mnemonic

Think of an **ITS** (逸) **U** (脱) **DATSU** (逸脱). A 'rabbit' (逸) trying to 'shed' (脱) its skin while running 'off the path.'

Visual Association

Imagine a train track where one wheel is lifted off the rail. The rail is the 'norm' and the wheel is 'itsudatsu.'

Word Web

Rules Standards Outliers Sociology Error Boundary Straying Divergence

Challenge

Try to find one example of 'itsudatsu' in a Japanese news article today. Look for it in the business or crime sections.

Word Origin

The word comes from Middle Chinese roots. '逸' (itsu) originally meant a rabbit running away or escaping, which evolved to mean 'to stray' or 'to be excellent (escaping the ordinary).' '脱' (datsu) means to shed, take off, or escape.

Original meaning: To escape or slip away from a path or boundary.

Sino-Japanese (Kango).

Cultural Context

Be careful when calling someone's behavior 'itsudatsu' to their face, as it sounds very clinical and judgmental.

In English, 'deviation' can be positive (innovation) or negative (error). In Japanese, 'itsudatsu' is usually formal/neutral but often implies a problem to be solved.

Howard Becker's 'Outsiders' is translated using 'Itsudatsu' in Japanese sociology. Japanese safety laws for Shinkansen use 'Itsudatsu' for derailment prevention. Merton's Strain Theory is taught as 'Itsudatsu riron' in Japan.

Practice in Real Life

Real-World Contexts

Business Meetings

予算からの逸脱
計画の逸脱
目的を逸脱した議論
仕様からの逸脱

Academic Writing

社会的な逸脱
理論からの逸脱
統計的な逸脱値
規範からの逸脱

Driving/Technical

車線逸脱警報
軌道逸脱
許容誤差の逸脱
安全基準の逸脱

Legal/Ethics

権限の逸脱
倫理からの逸脱
法の逸脱
逸脱行為の罰則

Psychology/Sociology

逸脱行動の研究
常軌を逸脱した精神状態
集団からの逸脱
自己の逸脱

Conversation Starters

"最近、常軌を逸脱したニュースが多いと感じませんか？ (Don't you feel there are many 'abnormal' news stories lately?)"

"仕事でマニュアルから逸脱してしまった経験はありますか？ (Have you ever had an experience where you deviated from the manual at work?)"

"議論が本来の目的から逸脱したとき、どうやって戻しますか？ (When a discussion deviates from the original purpose, how do you bring it back?)"

"芸術における「逸脱」は、美しさの一部だと思いますか？ (Do you think 'deviation' in art is part of its beauty?)"

"社会の規範から逸脱することについて、どうお考えですか？ (What are your thoughts on deviating from social norms?)"

Journal Prompts

あなたがこれまでに「常軌を逸脱している」と感じた出来事について書いてください。 (Write about an event you felt was 'deviating from the beaten path.')

目標から逸脱してしまったとき、どのように軌道修正をしますか？ (How do you correct your course when you deviate from your goals?)

もし社会のすべてのルールから逸脱できるとしたら、何をしたいですか？ (If you could deviate from all the rules of society, what would you want to do?)

「逸脱」と「創造性」の関係について、自分の意見を述べてください。 (State your opinion on the relationship between 'deviation' and 'creativity.')

最近の技術（AIなど）が人間のコントロールから逸脱する可能性についてどう思いますか？ (What do you think about the possibility of modern technology like AI deviating from human control?)

Frequently Asked Questions

10 questions

No, that's too small. Use 'machigai' or 'gaji'. Itsudatsu is for significant departures from rules or logic.

Usually, yes, in business and law. However, in art or creative fields, it can be neutral or even slightly positive if it means breaking boundaries.

Most commonly '〜から' (kara). In the idiom '常軌を逸脱する', use 'を' (o).

Only in specific technical terms like 'lane departure' (車線逸脱). For walking off a path, 'sore-ru' is more natural.

It means 'deviant behavior.' It is a common term in sociology and school discipline.

You can say 'itsudatsu-chi' (逸脱値) or 'hazure-chi' (外れ値).

You can, but 'dassen' (脱線) is more common for conversation.

Yes, it is typically found in N2 and N1 levels.

'Somoku' means to intentionally disobey a person or rule. 'Itsudatsu' is more about the state of being off-path.

Yes, 'itsudatsu suru' is very common.