行為|こういkoui[1]atamadaka (head-high)

1. nounact; deed; conduct
   彼かれは自分じぶんの行為こういを正当化せいとうかしようとしている。↗

   He is trying to justify his act.

• Synonym行いおこないNeutralOne's deeds, whether everyday conduct or a single act, as in 「親切な行い」; carries a moral judgement, while 「行為」 describes objectively.
• Synonym行動こうどうNeutralAction taken toward a purpose, as in 「行動に移す」; broader in scope than 「行為」.
• Synonym営みいとなみWrittenWritten style. Livelihood and human activity, as in 「人間の営み」; suggests ongoing activity of daily life.
• Synonym所作しょさWrittenWritten style. Physical movements and bearing, as in 「美しい所作」「所作を学ぶ」.
• Related振る舞いふるまいNeutralOne's outward manner or bearing, as in 「立ち居振る舞い」; focuses on external demeanor rather than the act itself.
• Related態度たいどNeutralAttitude or stance toward people or matters, as in 「態度が悪い」「反対の態度」; 「行為」 refers to concrete acts.
• Related仕業しわざNeutralA bad deed someone has done, as in 「誰の仕業だ」; carries a derogatory nuance.
• Related行儀ぎょうぎNeutralManners and propriety, as in 「行儀が悪い」; judges whether behavior is proper rather than the act itself.
• Related言動げんどうNeutralWords and deeds together, as in 「言動に注意する」; it names what one says alongside what one does.
• Related仕打ちしうちNeutralHarsh or cruel treatment of others, as in 「ひどい仕打ち」; derogatory.
• Related営為えいいWrittenWritten style. Human activity and enterprise; academic tone.
• Related行状ぎょうじょうWrittenWritten style. One's everyday conduct; evaluative.
• Related活動かつどうNeutralActivity, as in 「部活動」; ongoing undertakings rather than a single act.
• Related素行そこうWrittenWritten style. Everyday conduct, mostly in 「素行不良」; often negative.
• Related身持ちみもちNeutralOne's conduct or moral habits, and also pregnancy; rare in modern usage. 「行為」 refers to concrete acts.
• Related品行ひんこうWrittenWritten style. Moral conduct, as in 「品行方正」; viewed from a moral angle.
• Antonym不作為ふさくいWrittenWritten style. In law, failure to do what one should; the opposite of 「作為」. A related concept, not a direct antonym of 「行為」.
• Antonym無為むいWrittenWritten style. Idleness, doing nothing; contrasts with 「行為」 as deliberate action.

「行為」 is a deliberate act, common in legal and news contexts, as in 「違法行為」「親切な行為」. For one's deeds use 「行い」, for purposeful action 「行動」, and for words and deeds 「言動」. The others cover specific angles: manner (「振る舞い」「所作」), attitude (「態度」), manners (「行儀」), bad deeds (「仕業」「仕打ち」), moral conduct (「品行」「素行」「行状」「身持ち」), and ongoing activity (「営み」「活動」「営為」). 「無為」 (idleness) is the written-style opposite; 「不作為」 is only a related legal term, the counterpart of 「作為」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 人ひとが意志いしに基もとづいて行おこなう動作どうさ。
2. 人ひとの意思いしに基もとづく身体からだの動静どうせい。
3. 性交せいこうの婉曲えんきょく表現ひょうげん。性行為せいこうい。