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B1 noun 7 min read

不当

Practice it Examples Notes & Tips 不当 in 30 Seconds

Explanation 不当 in your Level:

At the A1 level, '不当' is quite advanced, but you can understand it as a more formal way of saying 'not good' (不好) or 'not right' (不对). Imagine you are playing a game and you make a move that isn't allowed—that could be '不当.' You might see it in very simple signs or instructions that tell you not to do something 'improperly.' It's like saying 'Don't do it that way!' in a very polite, serious voice. Focus on the '不' (no) part to remember it's a negative word. You don't need to use it yet, but recognizing it in a professional setting will help you understand that someone is talking about a mistake.

By A2, you can start to see '不当' as 'unsuitable.' While you usually use '不合适' (bù hé shì) for things like clothes that don't fit, '不当' starts to appear when talking about behavior. If a student is being too loud in a library, their behavior is '不当.' It's a useful word to recognize in short news clips or school rules. Think of it as 'not proper.' You might see it in phrases like '用词不当' (using the wrong word), which is something your teacher might write on your homework if you use a slang word in a formal essay. It helps you understand that Chinese has different 'levels' of politeness.

At the B1 level, you should begin using '不当' in your writing and formal speaking. This is the level where you move beyond 'good' and 'bad' and start using specific vocabulary. '不当' is perfect for discussing problems in a workplace or analyzing a situation. Instead of saying '他的方法不好' (His method is not good), you can say '他的处理方式不当' (His way of handling it was improper). This makes you sound much more professional. You should also learn common pairs like '行为不当' (improper behavior) and '管理不当' (mismanagement). It's an essential word for passing intermediate exams and having business conversations.

At the B2 level, you should understand the legal and social nuances of '不当.' You will encounter it in complex texts about law (like '不当得利' - unjust enrichment) and social issues. You should be able to distinguish '不当' from its close synonyms like '不妥' (inadvisable) and '失当' (improper/failed). At this level, you aren't just using the word; you are choosing it because it conveys a specific type of 'wrongness'—one that is about social standards, professional ethics, or procedural correctness. You can use it to critique policies or discuss the ethics of a situation in a debate. It's a key word for expressing sophisticated opinions.

For C1 learners, '不当' is a tool for precision. You should be able to use it as a noun-like object in sentences like '此举之不当，显而易见' (The impropriety of this move is obvious). You will see it used in historical analysis to describe the failures of past leaders or in high-level literary criticism to describe a writer's 'inappropriate' choice of tone. You should also be aware of its use in ancient-style formal prose (semi-literary Chinese) where '当' (dāng) has deep roots in the concept of 'justice' and 'appropriateness.' Your usage should be flawless, appearing in the correct register without sounding forced.

At the C2 level, '不当' is part of your instinctive grasp of the 'Lǐ' (propriety) in Chinese culture. You understand that '不当' is not just a vocabulary word but a reflection of a cultural emphasis on harmony and fitting into one's role. You can use it to discuss the finest points of philosophy, law, and diplomacy. You recognize it in classical poetry or legal codes from the Qing Dynasty. You can use it with total flexibility, perhaps even using it ironically in a very sophisticated joke or using its most obscure collocations in a doctoral thesis. It is no longer a 'new word' but a fundamental building block of your high-level linguistic identity.

Practice it Examples Notes & Tips

不当 in 30 Seconds

A formal Chinese word meaning 'inappropriate' or 'improper.'
Used for behavior, speech, management, and legal contexts.
More serious and objective than simple words like 'bad' or 'wrong.'
Common in professional reports, news, and formal apologies.

The Chinese term 不当 (bù dàng) is a formal and versatile word primarily used to describe things that are inappropriate, improper, or unsuitable for a given context. While it functions frequently as an adjective, in formal Chinese, it often occupies the role of a noun or a substantive descriptor indicating the state of 'improperness.' Understanding this word requires looking at its components: 不 (not) and 当 (proper/matching). When something is '不当,' it means there is a mismatch between an action and the social, legal, or logical environment it exists in.

Social Context: In social settings, it refers to behavior or speech that violates etiquette or causes discomfort. For example, '言语不当' (improper speech) might refer to using a joke that is too aggressive for a business meeting.
Legal and Administrative Context: In law, it appears in specific terms like '不当得利' (unjust enrichment), referring to the improper acquisition of wealth. In administration, '处理不当' (improper handling) describes a failure in management or procedure.

他的这种做法显然是不当的。(His way of doing things is clearly inappropriate.)

The word is significantly more formal than '不对' (wrong). While '不对' implies a binary of correct vs. incorrect, '不当' implies a nuance of degree, timing, or situational fitness. You might be 'right' in your facts but '不当' in your delivery. This is why it is the preferred term in news reports, formal apologies, and academic critiques. It suggests a lack of judgment rather than just a lack of knowledge.

由于操作不当，系统崩溃了。(Due to improper operation, the system crashed.)

Common Collocations: Commonly paired with nouns like 行为 (behavior), 措施 (measures), or 词语 (words) to indicate that these specific things lack propriety.

请指正文中的不当之处。(Please point out any inappropriate parts in the text.)

Using 不当 effectively involves placing it as a modifier or a predicative adjective that describes the quality of an action or state. In modern Chinese, it is frequently seen in the structure '[Noun/Action] + 不当'. For example, '用词不当' (improper use of words) or '管理不当' (mismanagement). Here, '不当' acts as a resultative or descriptive complement that evaluates how the action was performed.

As a Predicate: When used as a predicate, it often follows a subject that represents an abstract concept or a specific behavior. Example: '这种处理方式非常不当' (This way of handling things is extremely improper).

如果投资不当，你可能会损失所有的钱。(If you invest improperly, you might lose all your money.)

Another common structure is '不当的 + [Noun]'. This is the standard attributive usage. For instance, '不当的行为' (improper behavior). This structure is used to define the noun before it even performs an action. It sets a tone of formal disapproval. It is often found in legal documents where specific 'inappropriate' acts are prohibited.

这篇文章里有很多用词不当的地方。(There are many places in this article where words are used inappropriately.)

The 'Noun' Usage: In phrases like '指出其不当' (pointing out its impropriety), '不当' functions as the object of the verb, effectively acting as a noun. This is a hallmark of high-level, formal Chinese writing.

我们必须纠正这些不当的做法。(We must correct these improper practices.)

You are unlikely to hear 不当 in a casual conversation between friends at a hotpot restaurant. Instead, it is a staple of the professional, academic, and media spheres in China. When a news anchor reports on a corporate scandal, they will use '不当' to describe the executives' actions to maintain a neutral yet critical journalistic tone. It provides a level of objective distance that '错误' (wrong) does not.

In the Workplace: During performance reviews or project post-mortems, a manager might say, '这次项目的失败主要是因为资源分配不当' (The failure of this project was mainly due to improper resource allocation). It sounds more analytical and less like a personal attack than saying the manager 'did a bad job.'

法官认为他的言论构成了不当影响。(The judge ruled that his remarks constituted improper influence.)

In the world of Chinese social media, when a celebrity issues a formal apology (a '道歉信'), they almost always include a phrase like '深感言行不当' (Deeply feeling that my words and deeds were inappropriate). This is a standard part of the 'public relations' vocabulary in China. Similarly, in customer service, if a representative treats a customer rudely, the official response from the company will likely mention '服务不当' (improper service) as the reason for the disciplinary action.

政府正在调查这些不当的商业行为。(The government is investigating these improper business practices.)

The most frequent mistake learners make with 不当 is using it in contexts that are too casual. If you tell your friend their choice of shirt is '不当,' it sounds like you are a Victorian headmaster or a government official. In casual settings, use '不合适' (not suitable) or '不好看' (not good-looking) instead. '不当' carries a weight of moral or professional judgment that is out of place in personal friendships.

Confusing with '不对': Learners often use '不当' when they mean a factual error. If 1+1=3, that is '不对' (incorrect), not '不当'. '不当' is about the *appropriateness* of an action, not its mathematical or logical truth value.

Mistake: 这个单词的拼写不当。 (The spelling is inappropriate.)
Correct: 这个单词的拼写不对。 (The spelling is wrong.)

Another error is the placement of '不当' in a sentence. Because it often acts as a complement, learners sometimes forget to put the noun it modifies first. Remember: '处理不当' (handled improperly) is more common than '不当地处理' in many formal contexts, although both are grammatically possible. The former emphasizes the *state* of the handling, while the latter emphasizes the *manner* of the action.

由于对政策理解不当，他犯了一个错误。(Due to an improper understanding of the policy, he made a mistake.)

To master 不当, you must distinguish it from its synonyms. Each carries a different 'flavor' of inappropriateness. Choosing the right one will make your Chinese sound much more natural and precise.

不当 vs. 不妥 (bù tuǒ): '不妥' means 'not quite right' or 'unadvisable.' It is softer than '不当.' You use '不妥' when you have a gut feeling that a plan might fail or cause minor trouble. '不当' is more objective and often implies a violation of a standard.
不当 vs. 失当 (shī dàng): '失当' is very close to '不当' but emphasizes the *loss* (失) of propriety. It is often used in terms like '举措失当' (measures were improper). It sounds even more formal and is frequently found in historical or high-level political analysis.

我觉得这样做有些不妥。(I feel doing it this way is somewhat inadvisable.)

For everyday situations, 不合适 (bù hé shì) is the most common alternative. It simply means 'unsuitable.' If a pair of shoes doesn't fit, they are '不合适.' If you wear a swimsuit to a funeral, that is both '不合适' (unsuitable) and '不当' (improper). '不当' adds that layer of social or moral judgment.

这种药如果服用不当，会有副作用。(If this medicine is taken improperly, there will be side effects.)

How Formal Is It?

Fun Fact

In ancient Chinese law, '当' also meant 'to be sentenced to.' So '不当' could anciently imply an unfair sentence.

Pronunciation Guide

UK /buː dæŋ/

US /bu dɑŋ/

Second syllable (dàng) receives the falling tone stress.

Rhymes With

方 (fāng) 光 (guāng) 让 (ràng) 胖 (pàng) 唱 (chàng) 长 (zhǎng) 场 (chǎng) 上 (shàng)

Common Errors

Pronouncing 'dang' with a flat tone (it must be 4th tone).
Using the English 'a' sound (as in 'apple') for 'dang'.
Confusing 'dàng' with 'dāng' (1st tone), which means 'to be' or 'should'.
Over-emphasizing the 'bù' (it often undergoes tone sandhi to 2nd tone before a 4th tone).
Mumbling the 'ng' ending.

Difficulty Rating

Reading 3/5

Easy to recognize characters, but context matters.

Writing 4/5

Requires knowledge of formal collocations.

Speaking 4/5

Must be used in the right social register.

Listening 3/5

Common in news and formal announcements.

What to Learn Next

Prerequisites

不当合适错误行为

Learn Next

不妥失当恰当正当得体

Advanced

不当得利不当竞争显失公平违规

Grammar to Know

Resultative Complement

处理得不当 (Handled improperly).

Adjective as Noun

指出其不当 (Point out its impropriety).

Tone Sandhi (不)

bù + dàng -> bú dàng (tone changes to 2nd before 4th).

Attributive '的'

不当的行为 (Improper behavior).

Negation of '当'

不当 (Not proper) vs 应当 (Should).

Examples by Level

这样做不当。

Doing it this way is improper.

Simple Subject + Predicate.

说话不当。

Speaking improperly.

Verb + Adjective as a phrase.

他不当。 (Context: choice)

He is not the right one (for the role).

Short form usage.

这是不当的。

This is improper.

Using '的' to form an adjective phrase.

用词不当。

Improper use of words.

Common collocation.

行为不当。

Improper behavior.

Noun + Adjective.

不要不当。

Don't be improper.

Negative command.

他的方法不当。

His method is improper.

Possessive + Noun + Predicate.

他的言行非常不当。

His words and deeds are very improper.

Adverb of degree '非常' + Adjective.

由于处理不当，他生气了。

Due to improper handling, he got angry.

Cause and effect structure.

在学校里，这种行为是不当的。

In school, this kind of behavior is improper.

Prepositional phrase + Subject + Predicate.

请改正不当的地方。

Please correct the improper parts.

Imperative sentence.

他因为用词不当道歉了。

He apologized because of improper wording.

Reason structure '因为...而...'.

这是管理不当的结果。

This is the result of mismanagement.

Noun phrase as a complement.

那个决定显然是不当的。

That decision was obviously improper.

Adverb '显然' (obviously).

我们要避免不当的竞争。

We must avoid improper competition.

Verb '避免' + Object.

如果操作不当，机器可能会坏。

If operated improperly, the machine might break.

Conditional '如果...就...'.

由于他言语不当，引起了误会。

Because his speech was improper, it caused a misunderstanding.

Formal cause/effect.

这篇文章有很多用词不当之处。

There are many inappropriate uses of words in this article.

Noun '之处' (places/points).

他因为处理不当被公司开除了。

He was fired by the company due to improper handling.

Passive voice '被' structure.

这种不当的行为损害了公司的形象。

This improper behavior damaged the company's image.

Subject + Verb + Object.

我们应该纠正这种不当的倾向。

We should correct this improper tendency.

Abstract noun '倾向' (tendency).

由于管理不当，公司损失了一百万。

Due to mismanagement, the company lost a million.

Numerical result.

他意识到自己的做法非常不当。

He realized his way of doing things was very improper.

Mental state verb '意识到'.

这种做法被认为是对权力的不当使用。

This practice is considered an improper use of power.

Complex passive '被认为是'.

法律禁止任何形式的不当得利。

The law prohibits any form of unjust enrichment.

Legal terminology '不当得利'.

由于指挥不当，军队输掉了这场战斗。

Due to improper command, the army lost the battle.

High-level formal context.

我们必须对这些不当言论进行反驳。

We must refute these improper remarks.

Verb '进行' + Noun.

该官员因财务不当被调查。

The official is being investigated for financial impropriety.

Preposition '因' for reason.

如果不当处理废弃物，会造成污染。

If waste is handled improperly, it will cause pollution.

Environmental context.

他的辞职是因为舆论对其行为不当的批评。

His resignation was due to public criticism of his improper behavior.

Complex subject phrase.

该报告指出了政策执行中的不当之处。

The report pointed out the improprieties in policy execution.

Formal report style.

此项政策的制定过程存在严重的不当之处。

There are serious improprieties in the formulation process of this policy.

Formal '存在' (exist) structure.

他因涉嫌不当竞争而受到法律诉讼。

He faced legal action due to suspected unfair competition.

Legal term '不当竞争'.

这种不当的干预破坏了市场的自然平衡。

This improper intervention destroyed the market's natural balance.

Economic context.

文章对社会风气中的不当倾向进行了深刻批判。

The article deeply criticized the improper tendencies in social atmosphere.

Literary/Academic style.

由于翻译不当，原著的精髓未能完全表达。

Due to improper translation, the essence of the original work was not fully expressed.

Cultural/Literary context.

法院判定该合同条款因显失公平而不当。

The court ruled the contract terms improper due to obvious unfairness.

Advanced legal reasoning.

应当警惕媒体对青少年产生的不当影响。

One should be wary of the improper influence of media on teenagers.

Formal '应当' (should).

这种不当的资源分配导致了社会不公。

This improper resource allocation led to social injustice.

Sociological context.

其言辞之不当，足以令其政治生涯告终。

The impropriety of his words is enough to end his political career.

Classical '之' structure for noun-adjective relationship.

历史证明，任何对自然规律的不当挑战终将失败。

History proves that any improper challenge to the laws of nature will eventually fail.

Philosophical/Grand scale.

该学说因逻辑不当而难以自圆其说。

The theory is difficult to justify due to improper logic.

Academic idiom '自圆其说'.

这种不当的处世之道，最终使他陷入孤立。

This improper way of conducting oneself eventually led him into isolation.

Ethical/Philosophical context.

法律之严，在于不容许任何权力的不当行使。

The strictness of the law lies in not allowing any improper exercise of power.

Rhetorical '在于' structure.

我们需要审视那些被长期忽视的不当惯例。

We need to examine those improper conventions that have been ignored for a long time.

Critical analysis style.

由于时机选择不当，该项提议未获通过。

Due to improper timing, the proposal failed to pass.

Bureaucratic/Political nuance.

其行为背后隐藏着对法律底线的不当试探。

Behind his behavior lies an improper testing of the legal bottom line.

Psychological/Legal depth.

Common Collocations

行为不当

用词不当

处理不当

不当得利

管理不当

操作不当

言语不当

干预不当

投资不当

指挥不当

Common Phrases

不当之处

— Inappropriate points or aspects in a work or speech.

如有不当之处，请多多包涵。

不当竞争

— Unfair or illegal business competition.

公司被控告进行不当竞争。

举措不当

— Taking the wrong measures or steps.

由于举措不当，问题没有解决。

方法不当

— Using an incorrect or unsuitable method.

学习方法不当会浪费时间。

言行不当

— Inappropriate words and deeds.

公众人物应避免言行不当。

分配不当

— Improper distribution of resources or tasks.

资源分配不当会引起不满。

引用不当

— Incorrectly quoting someone or something.

这篇论文存在引用不当的问题。

宣传不当

— Improper or misleading advertising/promotion.

虚假宣传属于宣传不当。

饮食不当

— Improper diet or eating habits.

饮食不当会影响健康。

用人不当

— Hiring or assigning the wrong person for a job.

这次失败归咎于用人不当。

Often Confused With

不当 vs 不对

不对 is for factual errors (1+1=3); 不当 is for contextual/social errors (wearing a swimsuit to a funeral).

不当 vs 不妥

不妥 is 'unadvisable' or 'risky'; 不当 is 'improper' or 'violating a norm.'

不当 vs 不好

不好 is general 'bad'; 不当 is specifically 'inappropriate.'

Idioms & Expressions

"不当人子"

— Literally 'not acting like a human son.' Used to describe extremely unfilial or cruel behavior.

他竟然做出这种事，真是不当人子！

Literary/Archaic

"理所当然"

— As it should be; only natural. (Contains '当').

他努力工作，获得升职是理所当然的。

Common

"得当与否"

— Whether it is appropriate or not.

处理得当与否，关系到公司的前途。

Formal

"举措失当"

— Taking very inappropriate measures (Synonym phrase).

政府因举措失当受到批评。

Formal

"当之无愧"

— Fully deserving of a title or honor (Contains '当').

他是当之无愧的冠军。

Common

"大而无当"

— Large but useless; impractical.

这个计划大而无当，根本无法实施。

Common

"名不副实"

— The name does not match the reality (Related concept).

这家餐厅名不副实，菜并不好吃。

Common

"名副其实"

— The name matches the reality (Antonym concept).

他是名副其实的英雄。

Common

"安分守己"

— To know one's place and act properly.

他一直是一个安分守己的人。

Common

"不知好歹"

— Not knowing good from bad (Related to lack of judgment).

我是在帮你，你别不知好歹。

Informal

Easily Confused

不当 vs 失当

Both mean improper.

失当 emphasizes the 'failure' or 'loss' of propriety, often used for official measures (举措失当).

这次调控举措失当。

不当 vs 不宜

Both imply something shouldn't be done.

不宜 means 'not suitable' or 'not recommended' for a specific condition.

感冒时不宜运动。

不当 vs 欠妥

Both mean not quite right.

欠妥 is a softer, more polite way to say 'not quite appropriate.'

这个标题似乎欠妥。

不当 vs 无当

Contains the same character.

无当 usually appears in '大而无当' (large and useless).

他的计划大而无当。

不当 vs 不合

Both mean 'not matching.'

不合 is usually followed by a specific standard like '不合逻辑' (illogical) or '不合身' (doesn't fit the body).

这不合逻辑。

Sentence Patterns

这样做是不当的。

在图书馆大声说话是不当的。

由于...不当，导致了...。

由于管理不当，导致了亏损。

请指出...的不当之处。

请指出我报告中的不当之处。

...被认为是不当的。

这种商业行为被认为是不当的。

禁止...的不当使用。

禁止对权力的不当使用。

此举之不当，在于...。

此举之不当，在于忽视了民意。

涉嫌...不当。

他因涉嫌不当得利被调查。

不当之...，终将...。

不当之举，终将自食其果。

Word Family

Nouns

不当之处 (Inappropriate point)

不当得利 (Unjust enrichment)

Verbs

失当 (To be improper)

当做 (To treat as)

Adjectives

正当 (Legitimate)

妥当 (Appropriate)

恰当 (Apt)

应当 (Should)

当然 (Of course)

适当 (Suitable)

勾当 (Shady business)

上当 (To be fooled)

How to Use It

frequency

Common in written and formal spoken Chinese; rare in casual slang.

Common Mistakes

我的鞋子不当。 → 我的鞋子不合适。
'不当' is for behavior/ethics, not physical fit.
你这个字写得不当。 → 你这个字写错了。
'不当' isn't for simple spelling or stroke errors.
他是一个不当的人。 → 他的行为很不当。
'不当' describes actions or states, not a person's character directly.
这道题的答案不当。 → 这道题的答案不对。
'不当' is not for factual correctness.
我不当地去商店。 → 我去商店的方式不当。(If applicable)
'不当' is rarely used as a simple adverb of manner in casual speech.

Tips

Professional Tone

Use '不当' in emails to sound professional when addressing errors.

Collocation King

Memorize '行为不当' and '用词不当' as set phrases; they cover 50% of use cases.

Face Saving

Using '不当' instead of '错误' can help save face because it sounds more like a situational mismatch than a personal failure.

Legal Texts

If you see '不当' in a contract, pay close attention—it usually defines what NOT to do.

Tone Sandhi

Remember to change the tone of '不' (bù) to 2nd tone (bú) when followed by 'dàng'.

News Cues

When you hear '不当,' expect a critique or a report on a problem coming next.

Antonym logic

Learn '妥当' (proper) at the same time to understand the spectrum of the word.

Humility

End a formal speech with '如有不当之处，请多指教' to sound like a native.

HSK Tip

'不当' often appears in HSK 5 and 6 reading sections in the context of business or social ethics.

The 'Not-Proper' Rule

Always translate it as 'Not Proper' in your head to keep the formal nuance.

Memorize It

Mnemonic

Think of a 'DANG' (proper) bell ringing. If it's 'BU' (not) ringing correctly, it's 'BU DANG' (improper).

Visual Association

Imagine a square peg trying to enter a round hole. It is 'BU DANG' (not fitting/improper).

Word Web

Behavior Law Management Etiquette Mistake Formal Speech Context

Challenge

Try to find one '用词不当' (improper word use) in a social media post today and correct it.

Word Origin

Composed of '不' (negation) and '当' (to match/be suitable). The character '当' (traditional 當) originally depicted a field (田) and a base, implying value or matching value.

Original meaning: Originally referred to things not matching or not being of equal value, evolving into general inappropriateness.

Sino-Tibetan (Mandarin Chinese).

Cultural Context

Calling someone's behavior '不当' is a serious accusation in a Chinese workplace. Use it carefully.

English speakers often say 'That's not right,' which is broader. '不当' is specifically 'That's not appropriate for this setting.'

The term appears in the Civil Code of the People's Republic of China. Used in official CCTV news broadcasts regarding international relations. Common in the 'Analects' in the context of 'proper' behavior (though in classical form).

Practice in Real Life

Real-World Contexts

Business Management

管理不当
处理不当
资源分配不当
决策不当

Legal/Law

不当得利
不当竞争
程序不当
证据不当

Social Etiquette

言行不当
用词不当
礼仪不当
举止不当

Technical/Manuals

操作不当
使用不当
维护不当
安装不当

Education

方法不当
教育不当
引导不当
评价不当

Conversation Starters

"你认为这种处理方式有什么不当之处吗？"

"在你的国家，哪些行为会被认为是不当的？"

"如果你发现同事用词不当，你会提醒他吗？"

"你觉得媒体对青少年的不当影响严重吗？"

"由于操作不当，你曾经弄坏过什么贵重物品吗？"

Journal Prompts

描述一次你因为‘用词不当’而感到尴尬的经历。

讨论政府应该如何打击市场中的‘不当竞争’行为。

反思你过去的一个决定，是否有‘处理不当’的地方？你会如何改正？

写一段关于职场礼仪的短文，列举一些‘不当’的行为。

分析‘不当得利’在道德和法律上的区别。

Frequently Asked Questions

10 questions

Usually no. For a wrong answer (like 2+2=5), use '不对' or '错误.' Use '不当' if the *way* you answered was rude or inappropriate.

It is primarily an adjective, but in formal Chinese, it can function as a noun (e.g., '指出其不当' - point out its impropriety).

It is a legal term for 'unjust enrichment,' meaning getting a benefit at someone else's expense without a legal basis.

No. You would say '他行为不当' (His behavior is improper). '他不当' alone sounds incomplete.

Only in formal contexts like work emails, news, or serious discussions about behavior.

You can use '不当地' (bù dàng de) or simply use '不当' as a complement after the verb, like '处理不当'.

Yes, it always implies that something is not as it should be.

'不合适' is general (shoes don't fit); '不当' is formal/moral (behavior is improper).

Yes, '非常不当' or '极其不当' is very common to show the degree of impropriety.

'理所当然' (lǐ suǒ dāng rán) meaning 'it goes without saying' or 'it's only natural.'