How to say "motive" in Japanese

• 動機どうきJLPT N1approx.Common
  nounThe direct equivalent of 'motive': the inner drive or incentive that leads a person to act, as when discussing the motive for a crime or a decision.
  あの人ひとの動機どうきが信用しんようできなかった。↗

  I was distrustful of his motives.
• 本音ほんねJLPT N1approx.Common
  nounCovers 'motive' only in the sense of one's real intention or what one really thinks, as opposed to what one expresses outwardly; it is not a neutral word for the motive behind an action.
  世界せかいからは【麻疹ましん輸出国ゆしゅつこく】と嫌味いやみとも本音ほんねともとれることをいわれている始末しまつ。↗

  Ending up with being called a "measles exporting country" by the rest of the world, something that you could take as insult or truth.
• 理由りゆうJLPT N4approx.Common
  nounReally means 'reason' or 'grounds' — the explanation of why something was done — and can also suggest an excuse or pretext; it answers 'why?' but lacks the sense of an inner drive.
  どうしてあなたにお詫わびする理由りゆうがあるのですか。↗

  Why should I apologize to you?
• 心根こころねCommon
  nounIts core sense is a person's innermost feelings or heart — what they are really like deep down; it only marginally means 'motive', and is seldom the word you want when you mean a motive.
• 目的もくてきJLPT N3approx.Common
  nounMeans a purpose, goal or aim — the objective someone is trying to reach; it answers 'what for?' rather than 'what drove them?', so it is not the word for an inner motive.
  彼かれの目的もくてきはそのテストに合格ごうかくすることです。↗

  His object is to pass the test.

Use 動機 for the usual sense of 'motive', the inner drive behind an action; 本音 is for hidden true intentions, 理由 for reasons or excuses, 目的 for goals, and 心根 is seldom the right choice.

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

• 動機どうきmotive
• 本音ほんねreal intention
• 理由りゆうreason
• 心根こころねinnermost feelings
• 目的もくてきpurpose
• きっかけchance
• 誘因ゆういんcontributing cause
• 原動げんどうmotive
• 動因どういんdrive
• 了見りょうけんidea
• きかっけchance
• 思惑おもわくpurpose
• 縁由えんゆmotive (e.g. for an act)