眠い
ねむい
nemui
= sleepy; drowsy
眠い (nemui) captures that heavy-eyed, can’t-keep-your-lids-open feeling — the word Japanese speakers reach for the moment a lecture drags on, a commute turns monotonous, or a late-night chat session pushes past midnight.
眠い is an i-adjective meaning sleepy or drowsy — the subjective sensation of needing sleep right now. It inflects like any i-adjective: 眠くない (not sleepy), 眠かった (was sleepy), 眠くなる (to become sleepy), 眠すぎる (too sleepy to function). A close variant, 眠たい (nemutai), carries the same meaning but sounds slightly more expressive or childlike, often heard in Kansai speech and casual venting. Neither should be confused with 疲れた (tsukareta), which means tired/exhausted — you can be tsukareta without being nemui, for instance after a stressful day that leaves you wired. The noun form 眠気 (nemuke) refers to sleepiness as a state or wave of drowsiness, commonly seen in medicine warnings and product labels.
Learners sometimes mix up 眠い and 眠たい — both are natural, but 眠たい leans more colloquial and emotional. In formal writing or announcements, 眠気を感じる (to feel drowsiness) is preferred over 眠い. Also watch the conjugation trap: 眠い → 眠くない (NOT 眠いじゃない in standard grammar), and the intensifier drops the final い: 眠すぎる, not 眠いすぎる. To describe dozing off in the moment, pair nemui with うとうとする (uto-uto suru) — 眠くてうとうとしてしまった means “I was so sleepy I kept nodding off.”
The kanji 眠 pairs 目 (eye) on the left with 民 (people) on the right. 民 originally depicted a person with a downcast or closed eye — an image of subjects bowing before authority. Combined with 目, the character evokes eyes being cast downward and closed, visually encoding the act of shutting one’s eyes to sleep. The full character 眠 appears in 眠る (nemuru, to sleep), 眠気 (nemuke, sleepiness), and 不眠 (fumin, insomnia).
Everyday use
授業中、眠くて仕方なかった。
Jugyō-chū, nemukute shikata nakatta.
I couldn’t help being incredibly sleepy during class.
Casual / Social Media
眠いのにLINEの返信待ってる😴
Nemui noni LINE no henshin matteru 😴
So sleepy but waiting for a LINE reply 😴
Formal / Cultural context
眠気を感じましたら、すぐに運転をお控えください。
Nemuke o kanjimashitara, sugu ni unten o ohikae kudasai.
If you feel drowsy, please refrain from driving immediately.
Japan consistently ranks among the countries with the shortest average sleep duration in the world. The pressure of long working hours and lengthy commutes means 眠い is not just a passing complaint — for many salaried workers (会社員, kaishain), chronic sleepiness is a background condition of daily life. The phenomenon of karoshi (過労死, death from overwork) has drawn global attention to how severely sleep deprivation intersects with Japanese work culture, making 眠い a word loaded with social weight beyond simple tiredness.
Paradoxically, Japan has also developed a cultural tolerance — even subtle approval — for inemuri (居眠り), the practice of dozing in public places such as trains, meeting rooms, or classrooms. Rather than signaling laziness, inemuri can be read as proof that a person is working hard enough to be exhausted. This cultural nuance means that expressing 眠い openly, or visibly nodding off on a commuter train, carries far less social stigma in Japan than in many Western contexts.