How to say "reasoning" in Japanese

• 推理すいりJLPT N1approx.Common
  noun, suru verb, transitive verbReasoning in the sense of drawing conclusions from evidence, as in detective stories and puzzles; also inference and deduction. The everyday word for this mental activity.
• 理詰めりづめCommon
  no-adjectivePersuading or arguing by tightly reasoned logic rather than emotion; the reasoning behind a conclusion. Points to the rigorous, step-by-step quality of an argument.
• 論法ろんぽうCommon
  nounA line of argument or method of reasoning — how an argument is structured or conducted, as in discussing someone's 論法 in debate. Covers logic and argumentation more than deduction.
  その後ごまもなく私はクセノフォンの「ソクラテスの思い出おもいで」を手てに入いれたが、この中なかにはそれと同おなじ論法ろんぽうの実例じつれいがたくさんある。↗

  And soon after I procured Xenophon's Memorable Things of Socrates, in which there are many instances of the same method.
• 理路りろCommon
  nounThe logical thread or coherence of argument, often in 理路整然 ('clearly reasoned'). Seldom the standalone word for reasoning; it really names the logical order of thought or speech.
  あんな風ふうに理路りろ整然せいぜんと話はなされちゃうと、こっちは何なんも言いえないよな。↗

  What am I supposed to say when he puts it so logically?
• 推論すいろんCommon
  suru verb, transitive verb, no-adjectiveInference, deduction, and induction — reasoning as a formal process of deriving conclusions, common in academic or technical discussion. Heavier and more logical than 推理.
  言語げんごがどのように始はじまったのかについてはいくつも推論すいろんはあるが、実じつはだれもあまり知しらない。↗

  There are many guesses about how language began, but the fact is that no one really knows.

Use 推理 or 推論 for working out conclusions from evidence, while 論法, 「理詰め」, and 理路 concern logical argument and its construction or clarity.

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

• 推理すいりreasoning
• 理詰めりづめreasoning
• 論法ろんぽうlogic
• 理路りろlogic
• 推論すいろんinference