How to say "act" in Japanese

• 行為こういJLPT N1approx.Common
  nounThe word for 'act' as a deed or piece of conduct: something a person does, typically deliberately. Think of an act of kindness or violence — human behavior viewed as an action.
  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.
• 演ずるえんずるJLPT N1approx.Common
  ichidan verb (-zuru), transitive verbThe verb for the theatrical sense of 'act': to act a part or play a role, as a performer does on stage. It never refers to deeds or legislation.
• 法ほうJLPT N3approx.Common
  noun, noun (suffix)For 'act' in the legal sense of a law or statute. This is the general word for law, extending also to 'principle'; it has no connection with deeds or performing.
  すべての人ひとは法ほうの前まえに平等びょうどうです。↗

  Everybody is equal before the law.
• 法律ほうりつJLPT N4approx.Common
  nounThe usual word for 'law' and for legislation. Its 'act' sense is the legal one — a piece of legislation — so it answers to 'law' first; do not reach for it for acts in general.
  この法律ほうりつはすべての人ひとに適用てきようされる。↗

  This law applies to everybody.
• 法令ほうれいCommon
  nounA legal term covering statutes, laws, and ordinances; its 'act' sense belongs to official and legal writing. Seldom the word you want for 'act' generally — it really denotes written law as a category.
  その日ひは国会こっかいの法令ほうれいによって祝日しゅくじつになった。↗

  That day was made a holiday by an act of the diet.

Use 行為 for an act as a deed or conduct, 「演ずる」 for acting a part, and for the legal sense choose among 法, 法律, and 法令 — words for law and legislation, with 法令 covering statutes and ordinances.

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

• 行為こういact
• 演ずるえんずるto act (a part)
• 法ほうlaw
• 法律ほうりつlaw
• 法令ほうれいstatute
• 振る舞うふるまうto behave
• 行いおこないdeed
• 仕業しわざdeed (esp. negative)
• 興行こうぎょうshow
• 所業しょぎょうact (usu. undesirable)
• 演じるえんじるto act (a part)
• 仕打ちしうち(poor) treatment
• 所為しょいact
• 齣せきact (of a Chinese drama)
• アクトact
• 立ち振る舞うたちふるまうto act
• 役を勤めるやくをつとめるto act (as)
• 行動をとるこうどうをとるto act
• 起つたつto take action
• 業わざdeed
• 一芝居ひとしばいtrick
• 振りをするふりをするto pretend
• 演るやるto perform
• 阿南工業高等専門学校あなんこうぎょうこうとうせんもんがっこうAnan National College of Technology
• 動くうごくto make a move
• 勤めるつとめるto serve (as)
• 幕まくact (in a play)
• 働くはたらくto commit (e.g. a crime)
• ポーズpose
• 行こうact
• 立ち回るたちまわるto conduct oneself
• 小芝居こしばいlittle performance
• 出るでるto assume (an attitude)
• 立つたつto take action
• 段だんact (in kabuki, joruri, etc.)