不成功|ふせいこうfuseikou

1. na-adjective, no-adjectivefailure; abortive (attempt, action)
   成功せいこう不ふ成功せいこうは気質きしつに左右さゆうされることが多おおい。↗

   Success often depends on one's temperament.

• Synonym失敗しっぱいNeutralNeutral and the everyday word for failure. Covers not achieving something or making a mistake; far more common and ordinary than the written 「不成功」.
• Synonym挫折ざせつNeutralNeutral. Emphasizes being thwarted partway through and abandoning a goal mid-course; applies to plans and businesses alike.
• SynonymやりそこないCasualColloquial. Focuses on botching something in the doing — a slipup or blunder mid-task; more concrete and casual than 「不成功」.
• Synonym不結果ふけっかWrittenWritten and rare. Emphasizes the outcome — expected results failing to materialize; more narrowly result-focused than 「不成功」.
• Synonym不首尾ふしゅびWrittenWritten. Emphasizes a plan or affair turning out badly, and can also mean losing favor or popularity — a range 「不成功」 does not cover.
• SynonymしくじりCasualColloquial. A general word for failing at what you do, including through carelessness; looser and more casual than 「不成功」.
• Synonym遣り損じやりそんじWrittenWritten and rare. Emphasizes making an error or slip while doing something; narrower than 「不成功」's sense of an attempt failing.
• Related不出来ふできNeutralNeutral. Points to poor workmanship — work or results that turned out badly; concerned with quality and more concrete than 「不成功」.
• Related失態しったいWrittenWritten. Emphasizes a blunder that costs face — an embarrassing lapse damaging one's standing, not just an unsuccessful outcome.
• Related出来損ないできそこないCasualColloquial. Focuses on botched products or useless people — a defective article or a good-for-nothing — and carries an insulting tone 「不成功」 lacks.
• Related蹉跌さてつWrittenWritten and rare. Literally stumbling: emphasizes a stumble or setback along the way; mostly confined to formal prose.
• Antonym成功せいこうNeutralNeutral antonym: achieving one's aim — the very outcome 「不成功」 denies.

Use 「不成功」 in written or formal prose for attempts that come to nothing, as in 「不成功に終わる」; in everyday speech 「失敗」 is the usual word. For plans thwarted partway use 「挫折」, and colloquially 「しくじり」. The opposite is 「成功」.

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

1. 成功せいこうしないこと。上手うまく行いかないこと。また、そのようなさま。