睡眠|すいみんsuimin[0]heiban (flat)

1. no-adjectivesleep
   睡眠すいみんは薬くすりに勝まさる。↗

   Sleep is better than medicine.

• Synonym眠りねむりNeutralNative Japanese word for sleep or being asleep, with a literary flavor; it can also stand for death. 「睡眠」 is at home in both everyday and medical contexts.
• Synonym就眠しゅうみんWrittenWritten-style and rarely used; stresses the act of entering sleep — going to bed, falling asleep — whereas 「睡眠」 denotes the state of sleep itself.
• SynonymスリープNeutralLoanword mostly meaning a computer's low-power sleep mode; for people sleeping, 「睡眠」 is the usual word.
• Antonym覚醒かくせいWrittenWritten-style word for waking up or becoming alert — the opposite of 「睡眠」; figuratively, an awakening, coming to see the truth or one's own errors.

Use 「睡眠」 as the default, as in 「睡眠不足」 and 「睡眠時間」. 「眠り」 is the literary native word, as in 「深い眠り」. 「スリープ」 is for a computer's sleep mode. 「覚醒」 is the written opposite, waking up.

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

1. （すいみん）眠ねむること。眠ねむり。