怠惰|たいだtaida[1]atamadaka (head-high)

1. na-adjective, nounlazy; idle; indolent; slothful
   怠惰たいだは悪徳あくとくのもと。↗

   Idle hands are the devil's tool.

• Synonym無精ぶしょうNeutralNeutral: laziness centred on finding things too much bother to get moving; it also covers being unkempt, as in 「無精ひげ」.
• Synonym横着おうちゃくCasualColloquial: shirking and cutting corners — not doing what one should while still angling for a share of the benefits; has a brazen, cheeky edge.
• SynonymぐうたらCasualColloquial: a lazybones or good-for-nothing, idling the days away with no ambition; often names the person rather than the trait.
• Synonym懶惰らんだWrittenWritten and rare: the same laziness as the headword, stressing wasting time doing nothing at all.
• Related怠慢たいまんWrittenWritten/formal: negligence — failing to do what one is obliged to do; about dereliction of duty, not a lazy nature.
• RelatedずぼらCasualColloquial: sloppy and undisciplined — careless in what you do and slack in daily life, rather than laziness pure and simple.
• RelatedものぐさCasualColloquial: can't-be-bothered laziness; often describes a person who hates hassle and won't willingly lift a finger.
• RelatedけだるいNeutralNeutral: feeling languid and heavy for no particular reason — a passing bodily state, not a lazy character.
• Related物憂いものういWrittenWritten: languid because the mood is gloomy and listless; about low spirits sapping energy, not laziness as a trait.
• Related遊惰ゆうだWrittenRare and literary: idle and given to play, loafing about instead of working.
• Related不真面目ふまじめNeutralNeutral: not serious — a frivolous, insincere attitude rather than laziness itself.
• Related物憂げものうげWrittenWritten: a languid, melancholy look or air; describes the visible expression, not laziness itself.
• Related骨惜しみほねおしみCasualColloquial: begrudging one's effort — sparing yourself the work because it feels like too much trouble.
• Related惰気だきWrittenRare and written: a listless, lazy mood or state of mind.
• Related惰眠だみんWrittenWritten: idle slumber, mostly in the set phrase 「惰眠を貪る」 — sleeping the day away instead of doing anything.
• Related懈怠けたいWrittenMore bookish than the headword: laziness and slackness; read 「かいたい」, it also means neglecting one's duties.
• Related緩怠かんたいWrittenRare and written: slackness — letting your guard down and neglecting what should be done.
• Antonym勤勉きんべんNeutralAntonym: diligent and hard-working; the direct opposite of 「怠惰」.
• Antonym精励せいれいWrittenWritten antonym: single-minded, devoted hard work, contrasted with 「怠惰」 in formal prose.

For laziness in the sense of not making an effort, use 「怠惰」, a written-style word as in 「怠惰な生活」. When the point is finding things a bother, choose 「無精」 or 「ものぐさ」; for neglecting duties, 「怠慢」. Colloquial alternatives include 「ぐうたら」, 「横着」 and 「ずぼら」. The opposite is 「勤勉」.

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

1. 怠おこたり、怠なまけること。怠慢たいまん。