How to say "reasonable" in Japanese

• 当たり前あたりまえJLPT N2approx.Common
  no-adjective, na-adjectiveIt covers 'reasonable' as in natural or to be expected, as when something is just what anyone would assume. It really means 'obvious, a matter of course,' not reasonable prices or judgments.
  我々われわれは彼かれが成功せいこうしたのは当たり前あたりまえだと思おもった。↗

  We took his success for granted.
• 適正てきせいCommon
  na-adjective, nounCovers 'reasonable' as in appropriate and fair, meeting a proper standard or level. It judges whether something is suitable — neither excessive nor insufficient — rather than cheap.
• リーズナブルCommon
  na-adjectiveThe word for 'reasonable' about prices, fees, fares, and rates: fairly priced and affordable. It does not describe reasonable people, arguments, or assumptions.
• 順当じゅんとうCommon
  na-adjective, nounCovers 'reasonable' as in proper and right — a fair, expected outcome or conclusion. It is really about what is proper or follows the natural course, not about reasonable prices.
• 応分おうぶんCommon
  na-adjective, no-adjectiveCovers 'reasonable' only as proportionate: what is appropriate given a person's abilities. It really means 'according to one's abilities,' so it is seldom the word for general 'reasonable' judgments or prices.

For reasonable prices use 「リーズナブル」; for fair, appropriate levels or judgments use 適正; 「当たり前」 means natural or obvious, 順当 proper or right, and 応分 proportionate to one's abilities.

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

• 当たり前あたりまえnatural
• 適正てきせいreasonable
• リーズナブルreasonable (price, fee, fare, rate, etc.)
• 順当じゅんとうproper
• 応分おうぶんaccording to one's abilities
• 穏当おんとうproper
• 合理的ごうりてきrational
• 良心的りょうしんてきconscientious
• 当然とうぜんnatural
• まあまあso-so
• 正当せいとうjust
• 妥当だとうvalid
• 相応そうおうsuitable
• 値ごろねごろreasonable (price)
• 無理からぬむりからぬreasonable
• 聞き分けのいいききわけのいいreasonable (person)
• 故なしとしないゆえなしとしないreasonable
• 聞き分けがいいききわけがいいreasonable (person)
• 理のあるりのあるjustifiable
• 無理はないむりはないnatural
• 話のわかるはなしのわかるdown to earth
• 話がわかるはなしがわかるdown to earth
• 無理もないむりもないnatural
• 無理のないむりのないnatural
• あたぼうnatural
• あったりまえnatural
• 無理ないむりないnatural
• 筋道の通ったすじみちのとおったself-consistent (e.g. with one's morals)
• 至当しとうjust
• 穏やかおだやかmoderate
• もっともreasonable
• 手ごろてごろsuitable
• ごもっともreasonable
• 格好かっこうsuitable