役立つ・役だつ|やくだつyakudatsu[3]nakadaka (mid-high)
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Which spelling to use
役立つ役立つ（やくだつ） is the more common form and the recommended choice for beginners. Use it when writing this word as a learner.
役だつ役だつ（やくだつ） is a less common variant of 役立つ. Beginners should choose 役立つ instead.
Definitions
- godan verb, intransitive verbto be useful; to be helpful; to serve the purpose
Conjugation
| Dictionary form | 役立つ（やくだつ） |
|---|---|
| Polite (masu) | 役立ちます（やくだちます） |
| Negative (nai) | 役立たない（やくだたない） |
| polite (masen) | 役立ちません（やくだちません） |
| classical zu / nu | 役立たず・役立たぬ（やくだたず・やくだたぬ） |
| Past (ta) | 役立った（やくだった） |
| polite (mashita) | 役立ちました（やくだちました） |
| Past negative (nakatta) | 役立たなかった（やくだたなかった） |
| polite (masen deshita) | 役立ちませんでした（やくだちませんでした） |
| Te form | 役立って（やくだって） |
| Potential | 役立てる（やくだてる） |
| Passive | 役立たれる（やくだたれる） |
| Causative | 役立たせる（やくだたせる） |
| Causative passive | 役立たせられる・役立たされる（やくだたせられる・やくだたされる） |
| Conditional (ba) | 役立てば（やくだてば） |
| tara | 役立ったら（やくだったら） |
| Volitional | 役立とう（やくだとう） |
| polite (mashou) | 役立ちましょう（やくだちましょう） |
| Imperative | 役立て（やくだて） |
Common forms generated by rule; see the senses for honorific or irregular usage.
Transitive / intransitive pair
知識が役立つ
役立つ describes something as being useful or serving a purpose on its own (marked with が), while 役立てる describes a person actively putting something to practical use (marked with を).
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Synonyms & antonyms
- Synonym有益ゆうえきWrittenWritten adjectival noun for 'beneficial', as in 「有益な情報」; 「役立つ」 is a verb and common in everyday speech.
- Synonym有用ゆうようWrittenWritten adjectival noun meaning 'useful'; 「役立つ」 is a verb, so the two differ in part of speech as well as register.
- Synonym重宝ちょうほうNeutralCovers things that are handy and get used often, as in 「重宝する」; 「役立つ」 focuses on actually serving a purpose.
- Synonym資するしするWrittenWritten verb for contributing to something, as in 「発展に資する」; 「役立つ」 is more colloquial.
- Synonym役に立つやくにたつNeutralIdiomatic phrase with the same meaning as 「役立つ」, and more common in speech, as in 「役に立つ情報」.
- Synonym実用的じつようてきNeutralMeans practical and geared to real use; 「役立つ」 focuses on serving a purpose and helping.
- Synonym便利べんりNeutralThe everyday word for convenient, as in 「便利な道具」; 「役立つ」 focuses on serving a purpose.
- Related有意義ゆういぎNeutralMeans meaningful or worthwhile, as in 「有意義な時間」; 「役立つ」 focuses on doing its job.
- Related効果的こうかてきNeutralMeans effective, producing results, as in 「効果的な方法」; 「役立つ」 stresses being useful.
- Related貢献こうけんNeutralMeans contributing or contribution, as in 「社会貢献」; 「役立つ」 stresses being useful.
- Related便宜べんぎWrittenWritten noun for convenience, as in 「便宜を図る」; 「役立つ」 stresses being useful.
- Related手助けてだすけNeutralMeans lending a hand, usually with a person as the subject; 「役立つ」 typically describes things that are useful.
- Related好都合こうつごうNeutralMeans just right or convenient for one's own situation; 「役立つ」 focuses on being useful for a purpose.
- Related助けになるたすけになるNeutralMeans helpful to a person or thing, with either people or things as the subject; close in meaning to 「役立つ」.
- Related価値あるかちあるNeutralMeans valuable or worthwhile; 「役立つ」 stresses being actually usable and getting results.
- Related調法ちょうほうNeutralA separate word that is a homophone of 「重宝」 with a similar sense of convenience and practicality; 「役立つ」 focuses on doing its job.
- Related機能的きのうてきNeutralDescribes designs with strong functionality; 「役立つ」 stresses actually working and helping.
- Related適うかなうNeutralMeans fitting expectations, purposes or principles, as in 「目的に適う」; 「役立つ」 stresses being useful.
- Antonym無駄むだNeutralOpposite of 「役立つ」 in usefulness: effort that comes to nothing or is wasted.
- Antonym役立たないNeutralThe negative form of 「役立つ」, directly opposite to it in usefulness; it means useless.
For 'useful, does the job', choose 「役立つ」, or 「役に立つ」 in everyday speech. In written prose, use 「有益」 or 「有用」 for 'beneficial' and 「資する」 for 'contribute to'. For handy, convenient things, use 「重宝」 or 「便利」. The remaining words narrow the sense — 「効果的」 effective, 「貢献」 contributing, 「手助け」 helping, 「実用的」 practical, 「有意義」 worthwhile — and the opposites are 「役立たない」 and 「無駄」.
Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only
Japanese definitions
Kanji in this word
See also
