不能|ふのうfunou[0]heiban (flat)

1. na-adjective, nounimpossible; incapable (of doing); unable (to do)
   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.
2. nounincompetence; inability
3. nounimpotence
   不能ふのうになりました。↗

   I've become impotent.
4. noun, mathhaving no solution (of an equation)

• Synonym無理むりNeutralCommon in speech for what can't be done or is unreasonable, also overdoing or forcing things; 「不能」 is more written, mostly in compounds like 「再起不能」.
• Synonym不可能ふかのうNeutralSays something objectively cannot be achieved or done; the counterpart of 「可能」. 「不能」 mostly forms compounds and can also mean incompetence.
• SynonymありえないCasualSays something cannot happen; in speech it often means unbelievable or absurdly over the top.
• SynonymだめCasualColloquial and hugely versatile: no good, useless, not allowed; 「不能」 is written and means unable to do something or incompetent.
• Synonym無能むのうNeutralMeans incompetent or lacking ability and often serves as an insult; 「不能」 stresses being unable to do something.
• Related非力ひりきNeutralMeans weak or short on strength and ability; 「不能」 means unable to do something, and also lack of ability.
• Related無力むりょくNeutralMeans powerless, as in 「無力感」; stresses lacking the strength to change a situation.
• Related能がないのうがないCasualColloquial for having no ability or talent, often said as 「…しか能がない」.
• Related勤まらないつとまらないNeutralMeans one cannot handle a post or is unequal to a role; use is limited to work and positions.
• Related無才むさいWrittenWritten word for lacking talent, often used humbly about oneself.
• Related無能力むのうりょくWrittenWritten word for lacking the ability to do something, also a term from the old Civil Code; leans more toward lack of ability than 「不能」.
• Antonym可能かのうNeutralMeans something can be realized or done — the opposite of 「不能」.

For what cannot be done, everyday speech uses 「無理」 or 「できない」, while 「不可能」 suits written or formal contexts. 「不能」 itself mostly appears in compounds like 「再起不能」 and 「制御不能」, or refers to incompetence.

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

1. 才能さいのうが無ないこと。無能むのう。
2. することが出来できないこと。不可能ふかのう。
3. 性的せいてき能力のうりょくのないこと。性的せいてき不能ふのう。
4. 方程式ほうていしきの解かいを求もとめることができないこと。解かい不能ふのう。