行 為(こうい)

こうい

noun

act, action, conduct

formalaction

See also: 好意(こうい) (goodwill, kindness)

1. act, action, deed, conduct, behavior

A deliberate action or deed performed by a person, often used in formal or legal contexts.

違法(いほう)行為(こうい)は許(ゆる)されない。

Illegal acts are not permitted.

その行為(こうい)は法律(ほうりつ)に違反(いはん)する。

That act violates the law.

彼(かれ)の行為(こうい)は多(おお)くの人(ひと)を傷(きず)つけた。

His actions hurt many people.

行為(こうい) is a formal word for "act" or "action," commonly used in legal and official contexts.

Etymology

行(こう) (go, do) + 為(い) (act, do) = act, deed

Compounds

違法(いほう)行為(こうい): illegal act
犯罪(はんざい)行為(こうい): criminal act
不法(ふほう)行為(こうい): unlawful act
暴力(ぼうりょく)行為(こうい): act of violence
性(せい)行為(こうい): sexual act
自傷(じしょう)行為(こうい): self-harm
背信(はいしん)行為(こうい): act of betrayal

Similar words

行動(こうどう): action, behavior (more general, everyday)
振(ふ)る舞(ま)い: behavior, conduct
所業(しょぎょう): deed, act (often negative)

Usage

行為(こうい) is more formal and often implies moral or legal judgment compared to 行動(こうどう).

Related Words

Synonym: 行動(こうどう) (action (everyday))

Compare: 振(ふ)る舞(ま)い (behavior, conduct)

general

Added 2026.2.4 22:51 · Revised 2026.10.6 9:22

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