徒|あだada[2]odaka (tail-high)

1. na-adjective, nounvain; futile; transient; frivolous

• SynonymはかないNeutralFor what soon slips away — brief lives, dreams, hopes. 「徒」 instead stresses effort or kindness coming to nothing, often as 「徒となる」.
• Synonym虚しいむなしいNeutralEmpty and futile, stressing the hollow feeling left inside, as in 「虚しい努力」. 「徒」 names the wasted effort or kindness itself, not the feeling.
• Synonym無益むえきWrittenWritten/formal: what brings no benefit or gain, as in 「無益な争い」. Close to 「徒」 in sense but more bookish.
• Synonym無用むようWrittenWritten/formal: stresses being unneeded or superfluous, as in 「心配無用」. 「徒」 stresses being wasted, not merely unnecessary.
• Synonym不毛ふもうWrittenWritten/formal: literally barren land; figuratively discussion that yields no results, as in 「不毛な議論」.
• Synonym詮無いせんないWrittenLiterary and archaic: no use in doing it, no help for it. Older in flavor than 「徒」.
• Synonym徒爾とじWrittenA rare, stiff Sino-Japanese word for futility; same sense as 「徒」 but confined to formal writing.
• RelatedだめCasualThe everyday colloquial word for no good or useless; far broader in use than the literary 「徒」.
• Antonym実じつWrittenAntonym: truth, sincerity, real substance — the opposite of the unreal, empty 「徒」.
• Antonym誠まことNeutralAntonym: sincerity, good faith — opposes the frivolous, insincere side of 「徒」.
• Antonym益えきWrittenAntonym: benefit, profit, as in 「益がない」 — the direct opposite of the no-gain sense of 「徒」.

Use 「徒」 when kindness or effort is wasted or even backfires, as in 「親切が徒となる」 or 「徒花」. For what fleetingly passes, choose 「儚い」; for the hollow, futile feeling, 「虚しい」; in everyday speech, plain uselessness is 「駄目」. 「無益」「無用」「不毛」「詮無い」「徒爾」 serve as written-style alternatives. The opposites are 「実」「誠」 and 「益」.

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

1. 無意味むいみで役やくに立たたないこと。また、そのような様子ようす。