How to say "impossible" in Japanese

• 不能ふのうCommon
  na-adjective, nounCovers 'impossible' in terms of inability: being incapable of doing something or unable to do it. Suits contexts where an action cannot be carried out, rather than events that cannot happen or be true.
  説得せっとく不能ふのうを感知かんちしてか、黒崎くろさき先生せんせいはため息いきをついて席せきに着ついた。↗

  Perhaps having realized it was impossible to persuade her, Ms. Kurosaki sighed and sat down in her seat.
• 不可能ふかのうCommon
  na-adjective, nounThe straightforward word for 'impossible' as a property of a task, plan, or goal that cannot be done or achieved. Use it when stating flatly that something is impossible.
  回復かいふくはほとんど不可能ふかのうだった。↗

  Recovery was almost impossible.
• ありえないCommon
  i-adjectiveCovers 'impossible' in the sense of something that cannot happen or be true. Typical when reacting to a claim or outcome with disbelief — 'that's impossible!' — rather than judging a task unachievable.
  それは決けっしてありえない。↗

  That'll be a cold day in hell.
• 論外ろんがいCommon
  na-adjective, no-adjectiveCovers 'impossible' only as 'out of the question': a proposal or idea dismissed as not even worth considering, sometimes with a critical overtone. Not the word for a task that cannot be done.
  この前まえの娘むすめは口述こうじゅつ内容ないようを筆記ひっきするのも無理むりだった。速記そっきなんて論外ろんがいさ。↗

  That girl couldn't take things down in longhand, let alone shorthand.
• 難しいむずかしいJLPT N5approx.Common
  i-adjectivePrimarily means 'difficult', but serves euphemistically for 'impossible' or 'unfeasible' — a soft way of saying something cannot be done, as when turning down a request without refusing outright.

Choose 不可能 for a task or plan that cannot be done, 「ありえない」 for things that cannot happen or be true, 不能 for inability to do something, 論外 for 'out of the question', and 「難しい」 as a euphemistic 'unfeasible'.

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

• 不能ふのうimpossible
• 不可能ふかのうimpossible
• ありえないimpossible
• 論外ろんがいout of the question
• インポシブルimpossible
• ポコペンimpossible
• 叶わぬかなわぬimpossible (dream, wish, etc.)
• 問題外もんだいがいout of the question
• 見果てぬみはてぬunfinished
• 困ったこまったunmanageable
• 難しいむずかしいimpossible
• 無理むりimpossible
• かなわないunable to do
• あられもないunthinkable
• 世話がないせわがないhopeless (person)
• ならぬbeyond one's power
• ないnot