才|さいsai[1]atamadaka (head-high)

1. nounability; gift; talent; aptitude; genius
   われわれのすべてが生うまれつき音楽おんがくの才さいがあるわけではない。↗

   Not all of us are born with musical talent.
2. nounsai; traditional unit of volume, approx. 1.8 ml

• Synonym才能さいのうNeutralThe standard, most common word for talent or ability. 「才」 on its own mostly appears in 「…の才がある」 or in compounds, and leans written.
• Synonym才気さいきWrittenWritten word for brilliance, as in 「才気あふれる」; stresses intelligence that shows outwardly, with a sharp edge.
• Synonym能のうNeutralColloquial for ability, mostly in 「能がない」; also names the noh theatre, so context matters.
• Synonym力量りきりょうNeutralCapability or capacity; stresses real, demonstrated strength, as in 「力量を発揮する」.
• Synonym才知さいちWrittenWritten word for wit and intelligence; stresses brightness of mind rather than skill in a field, unlike 「才」.
• Synonym才力さいりょくWrittenRarely used even in writing; say 「才能」 or 「実力」 instead.
• Synonym才腕さいわんWrittenWritten word for executive skill, as in 「才腕を振るう」; stresses deft handling of practical business.
• Synonym才幹さいかんWrittenWritten word for administrative ability; often used to evaluate officials or business executives.
• Synonym才分さいぶんWrittenRare even in writing; stresses the talent or disposition one is born with, while 「才」 covers talent in a field more generally.
• Synonym天賦の才てんぷのさいWrittenA phrase for innate talent; stresses that the gift is inborn and sounds more formal than 「才」.
• Related知恵ちえNeutralEveryday word for wisdom and ideas; stresses thinking up solutions, a different focus from talent in a field.
• Related技量ぎりょうNeutralSkill or competency; stresses technical level, as in 「技量を磨く」, rather than innate gift.
• Related英才えいさいWrittenWritten word for outstanding talent or a gifted person, as in 「英才教育」.
• Related天才てんさいNeutralExtraordinary inborn ability, or its possessor; common in speech, as in 「天才だ」. 「才」 is more written and usually talent in one field.
• Related素質そしつNeutralMakings or aptitude; stresses potential that can be developed, not ability already shown.
• Related知能ちのうNeutralIntelligence in a psychological sense, as in 「知能指数」; not talent in a particular art or skill.
• Related知力ちりょくNeutralMental capacity or comprehension; stresses brainpower, as in the 「知力」 stat in games.
• Related機知きちNeutralWit and tact; stresses quick, adaptable thinking in the moment, not talent in a field.
• RelatedウイットNeutralLoanword for wit; stresses humorous, clever turns of speech rather than ability.
• Related英気えいきWrittenWritten word for outstanding brilliance, and also for vigor; often in 「英気を養う」.
• Related俊才しゅんさいWrittenWritten word for a person of exceptional talent; points to the person rather than the ability itself.
• Related異才いさいWrittenWritten word for a rare, one-of-a-kind talent; stresses being unlike others.
• RelatedとんちNeutralReady wit, a flash of cleverness in the moment, as in 「一休さんの頓知」.
• Antonym愚ぐWrittenAntonym: foolishness, the opposite of 「才」; also a humble way to say 'I'.

「才」 is a written-flavoured word for talent, used mostly in compounds or in 「…の才がある」, as in 「音楽の才がある」. For talent in general say 「才能」; for an inborn gift, 「天賦の才」; for wisdom, 「知恵」; for wit, 「機知」. The opposite is 「愚」.

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

1. （サイ 古語こご:ざえ）あることに秀ひいでた能力のうりょく。
2. （サイ）年齢ねんれいを数かぞえる助数詞じょすうし「歳とし」に代かえ俗用ぞくようされるもの。