When do I use 无 vs 非?

Use 无 when you mean 'without' or 'lacking' something (e.g., 无限 wúxiàn 'unlimited'). Use 非 when you mean 'not' in the sense of 'not being X' or 'non-X' (e.g., 非专业 fēizhuānyè 'non-professional'). Think: 无 = absence, 非 = negation of identity.

Can 无 and 非 be used interchangeably?

No. While both are literary negators, they are not interchangeable because they negate different aspects. 无效 (invalid) and 非法 (illegal) have distinct meanings. However, a few compounds have both forms with different meanings: e.g., 无意 (wúyì 'unintentional') vs 非意 (fēiyì 'inappropriate meaning', rare).

Are 无 and 非 the same as 不 or 没?

No. 不 and 没 are versatile modern negators for verbs and adjectives, while 无 and 非 are bound prefixes limited to literary/formal compounds. You cannot replace 不 with 无 in everyday speech (e.g., 不吃 not ✅ 无吃).

Is 非 always a negative prefix?

In modern compounds, yes. But in classical Chinese, 非 also functions as a verb meaning 'to be wrong' or in the construction 非...不可 meaning 'must'. These are advanced usages.

Easily confusedHSK 6

无 vs 非 (wú vs fēi): literary negative prefixes

Both 无 (wú) and 非 (fēi) are bound literary morphemes used to form negative compounds, common in formal and written Chinese. 无 means “without, lacking” and negates existence or possession (e.g., 无效 wúxiào “ineffective”), while 非 means “not, non-” and negates identity or category (e.g., 非法 fēifǎ “illegal”). The key distinction: 无 negates what is absent or missing; 非 negates what is not the case or does not belong.

无 (wú) and 非 (fēi) are classical Chinese negators that survive in modern written and formal compounds. 无 conveys the idea of “lacking” or “without” - it negates the existence or presence of something (e.g., 无数 wúshù “countless”, 无耻 wúchǐ “shameless”). 非 conveys the idea of “not being” or “opposite of” - it negates the identity, classification, or correctness of something (e.g., 非正式 fēizhèngshì “informal”, 非暴力 fēibàolì “non-violent”). Neither can be used freely as a replacement for 不 (bù) or 没 (méi); they are fixed in set phrases and compound words. Choosing the correct prefix depends on whether the meaning is “absence of” (无) or “not belonging to / contrary to” (非).

When to use each

无wú

without, lacking

Use 无 in compounds where the meaning is the absence or lack of something, especially with nouns or verbs that imply possession or existence. It is common in formal, academic, and legal contexts (e.g., 无效 wúxiào 'invalid', 无关 wúguān 'unrelated', 无限 wúxiàn 'unlimited').

In classical-style four-character idioms, 无 may appear paired with 有 (yǒu) to express contrasts (e.g., 无中生有 wúzhōngshēngyǒu 'make something out of nothing').

非fēi

non-, not

Use 非 in compounds that negate the category, nature, or correctness of something - equivalent to 'not being X' or 'non-X'. It is widespread in formal, legal, and technical language (e.g., 非法 fēifǎ 'illegal', 非政府组织 fēizhèngfǔ zǔzhī 'non-governmental organization', 非暴力 fēibàolì 'non-violent').

非 also appears in the construction 非...不可 (fēi...bùkě) meaning 'must' (literally 'if not...then not acceptable').

At a glance

	无	非
Core meaning	absence / lack of X	negation of identity / 'not X'
Typical context	compounds describing missing qualities (e.g., 无耻 'shameless')	compounds describing what something is not (e.g., 非会员 'non-member')
Common examples	无效 wúxiào (invalid, without effect)	非法 fēifǎ (illegal, not legal)
Can it stand alone?	Only in literary phrases	Only in classical quotes or set expressions
Formal register	Yes, typical in written Chinese	Yes, especially in legal and academic language

Examples

无
这个合同无效。
Zhè ge hé tong wú xiào.
This contract is invalid.
无效 = without effect; 无 indicates absence of legal effect.
非
这是非法停车。
Zhè shì fēi fǎ tíng chē.
This is illegal parking.
非法 = not legal; 非 negates the legality of the action.
无
他真是无耻之徒。
Tā zhēn shì wú chǐ zhī tú.
He is truly a shameless person.
无耻 = without shame; 无 negates the existence of shame.
非
这是一个非正式会议。
Zhè shì yí gè fēi zhèng shì huì yì.
This is an informal meeting.
非正式 = not formal; 非 negates the status of being formal.
无
他无法按时完成。
Tā wú fǎ àn shí wán chéng.
He is unable to finish on time.
无法 = no way; 无 indicates absence of method.
非
✗他非法按时完成。
✗ Tā fēi fǎ àn shí wán chéng.
(Intended: He cannot finish on time.)
✗ Wrong: 非法 means 'illegal', not 'unable'. Use 无法.

Common mistakes

Using 非法 (fēifǎ) to mean 'unable' instead of 无法 (wúfǎ).
Using 无 for negation of category, e.g., saying 无政府组织 for 'non-governmental organization' instead of 非政府组织.
Confusing 非 by using it to mean 'without', e.g., 非效 instead of 无效.
Omitting the correct prefix in set academic terms like 非营利 (fēiyínglì 'non-profit') — incorrectly saying 无营利.

FAQ

When do I use 无 vs 非?: Use 无 when you mean 'without' or 'lacking' something (e.g., 无限 wúxiàn 'unlimited'). Use 非 when you mean 'not' in the sense of 'not being X' or 'non-X' (e.g., 非专业 fēizhuānyè 'non-professional'). Think: 无 = absence, 非 = negation of identity.
Can 无 and 非 be used interchangeably?: No. While both are literary negators, they are not interchangeable because they negate different aspects. 无效 (invalid) and 非法 (illegal) have distinct meanings. However, a few compounds have both forms with different meanings: e.g., 无意 (wúyì 'unintentional') vs 非意 (fēiyì 'inappropriate meaning', rare).
Are 无 and 非 the same as 不 or 没?: No. 不 and 没 are versatile modern negators for verbs and adjectives, while 无 and 非 are bound prefixes limited to literary/formal compounds. You cannot replace 不 with 无 in everyday speech (e.g., 不吃 not ✅ 无吃).
Is 非 always a negative prefix?: In modern compounds, yes. But in classical Chinese, 非 also functions as a verb meaning 'to be wrong' or in the construction 非...不可 meaning 'must'. These are advanced usages.