LESSON NOTES · レッスンノート

N5Lesson notes · Oct 2, 2026

Sleepy in Japanese: how do you say 眠ねむい (nemui) and its relatives?

"Sleepy" in Japanese is 眠ねむい (ねむい, nemui) — an i-adjective for the feeling of wanting to sleep — and 眠ねむいです is the polite way to say "I'm sleepy."

That one word gets you through most days. But Japanese has a whole small family around it: a casual slang shortening, a "starting to get sleepy" form, a "looks sleepy" form for other people, a word for the sleepiness itself, and a cute sound word for dozing off. This article sorts them out so you can pick the right one instead of saying 眠ねむい about everything.

The basics

What is "sleepy" in Japanese, in hiragana and kanji?

The word is 眠ねむい, written in hiragana as ねむい. People write both. The kanji 眠みん appears in most of the family, so it is worth learning once: 眠ねむい, 眠気ねむけ, 眠ねむる, 眠ねむそう.

眠ねむい。 — I'm sleepy. (casual, to yourself or a friend) 眠ねむいです。 — I'm sleepy. (polite, safe with anyone) ちょっと眠ねむいです。 — I'm a little sleepy. (polite, softened with ちょっと)

Because it is an i-adjective, it conjugates like 高たかい or 暑あつい: 眠ねむくない (not sleepy), 眠ねむかった (was sleepy), 眠ねむくなかった (wasn't sleepy), 眠ねむくて (sleepy and... / because sleepy).

How do you say "I'm so sleepy" or "not sleepy at all"?

Stack the usual adjective tools on top.

すごく眠ねむい。 — I'm really sleepy. (casual) 眠ねむすぎる。 — I'm way too sleepy. (casual, すぎる = too much) 全然ぜんぜん眠ねむくない。 — I'm not sleepy at all. (casual, 全然ぜんぜん goes with a negative) 眠ねむくて死しにそう。 — I'm so sleepy I could die. (casual, an exaggeration friends really do say)

How do you say "I'm getting sleepy"?

Use 眠ねむくなる — "to become sleepy." It describes the change, not the state.

だんだん眠ねむくなってきた。 — I'm getting sleepier and sleepier. (casual, the feeling is creeping in) ごはんを食たべたら眠ねむくなった。 — After eating, I got sleepy. (casual, the classic post-lunch slump)

眠ねむい is the state you are in right now. 眠ねむくなる is the moment it begins. Learners often use 眠ねむい for both and miss the nuance of "it's coming on."

How is 眠ねむい different from 眠ねぶたい?

Both mean sleepy. 眠ねぶたい is a little softer and more drawn-out, and it often sounds a bit childlike or gentle, like someone rubbing their eyes. 眠ねむい is the neutral everyday choice.

ママ、眠ねぶたい。 — Mom, I'm sleepy. (childlike, soft) 今日きょうは朝あさから眠ねぶたいなあ。 — I've been sleepy since the morning. (casual, sleepy and a bit dreamy)

If you are unsure, use 眠ねむい. You will never sound wrong with it, while 眠ねぶたい can make an adult sound a little sing-song depending on the context.

Is 眠ねむい the same as 疲つかれた?

No, and this is a very common mix-up. 眠ねむい is about wanting to sleep. 疲つかれた is about being worn out. You can be tired and wide awake after a long day of sightseeing, and you can be sleepy after a calm afternoon.

疲つかれたけど、眠ねむくない。 — I'm tired, but I'm not sleepy. (casual, the two words are separate) 昨日きのうあまり寝ねてないから、眠ねむい。 — I didn't sleep much yesterday, so I'm sleepy. (casual, cause and effect)

For the tired side of this, see Japanese words for tired.

Beyond the basics

What do friends actually say instead of 眠ねむい?

In real speech 眠ねむい gets squashed, stretched, and sprinkled with sounds.

ねむー。 — Sleeeepy. (casual, the final vowel is stretched) ねみー。 — Sleepy. (very casual, rough or male-coded, mostly among close friends) 眠ねむいー、もう無理むり。 — I'm sleepy, I can't take it anymore. (casual, whining)

ねみー drops the む into み. It sounds relaxed and a bit rough, so keep it for friends and family. ねむー is softer and works for almost anyone you are comfortable with.

How do you say that someone else is sleepy?

Here is a rule that surprises many learners: a plain statement of someone else's inner feeling sounds odd in Japanese. You can say 私わたしは眠ねむい because you feel it. But 彼かれは眠ねむい sounds like you are reading his mind.

Instead, mark that you are judging from the outside:

彼かれ、眠ねむそうだね。 — He looks sleepy, doesn't he? (casual, you see it on his face) 彼かれは眠ねむいみたい。 — He seems to be sleepy. (casual, a guess from clues) 先生せんせいは眠ねむいらしいよ。 — I hear the teacher is sleepy. (casual, based on information)

The pattern with そう is built by dropping the い: 眠ねむい → 眠みんそう. It means "looks sleepy" and is based on what you can see. For the difference between looks-like and heard-that, see 〜そうです: looks like vs. I heard, and for みたい and らしい see みたい, らしい, ようだ.

Pattern Meaning Based on
眠ねむい I am sleepy Your own feeling (first person)
眠ねむそう looks sleepy What you can see
眠ねむいみたい seems sleepy A guess from several clues
眠ねむいらしい apparently sleepy Something you heard
眠ねむいって (they) say they're sleepy A direct quote, casual

What is 眠気ねむけ, and what is 眠気ねむけ覚さまし?

眠気ねむけ (ねむけ) is the noun: sleepiness, the drowsy feeling. It is what hits you. 眠気ねむけ覚さまし is something that wakes you up: coffee, gum, a cold splash of water.

眠気ねむけがすごい。 — I'm so drowsy. (casual, 眠気ねむけ as the subject) 眠気ねむけ覚さましにコーヒーを飲のむ。 — I'll drink coffee to wake myself up. (neutral, a common reason clause) 会議中かいぎちゅうに眠気ねむけが来きた。 — Sleepiness hit me during the meeting. (neutral)

You can also say 眠気ねむけを我慢がまんする (to fight off sleepiness) and 眠気ねむけが取とれない (I can't shake the drowsiness).

How do you say "I didn't sleep enough"?

The word is 寝不足ねぶそく (ねぶそく), lack of sleep. It is the most common reason people give for being sleepy.

寝不足ねぶそくで眠ねむい。 — I'm sleepy from lack of sleep. (casual, the standard explanation) 昨日きのうは寝不足ねぶそくだった。 — I didn't get enough sleep yesterday. (casual)

Jet lag has its own word with its own story; see jet lag in Japanese: 時差じさぼけ.

What does うとうと mean?

うとうと is the sound-word for dozing: half asleep, nodding off, not quite out. Japanese is full of these sound-and-feeling words (see Japanese onomatopoeia), and this one is gentle and warm.

電車でんしゃでうとうとしてしまった。 — I dozed off on the train. (casual, しまった adds a small "oops") ソファでうとうとしていた。 — I was dozing on the sofa. (casual)

Compare with ぐっすり (sleeping soundly): ぐっすり寝ねた means you slept deeply, うとうとした means you only drifted.

Is 寝ねる the same as 眠ねむる?

They overlap, but they are not the same. 寝ねる (ねる) is the everyday word: go to bed, lie down, sleep. 眠ねむる (ねむる) is more about being in the state of sleep, and it sounds a little more literary or soft.

もう寝ねるね。 — I'm going to bed now. (casual, the normal phone sign-off) 赤あかちゃんがぐっすり眠ねむっている。 — The baby is sound asleep. (neutral, state of sleep) 昨日きのうは何時間なんじかん寝ねた? — How many hours did you sleep yesterday? (casual)

The easy rule: if you are saying "I'm off to bed," use 寝ねる. 眠ねむる describes the condition of being asleep. 眠ねむい is the adjective that points toward both. For night-time phrases, see good morning and good night in Japanese.

How do you say it politely, like at work?

眠ねむいです is grammatically polite, but at work or with a teacher it can still sound too direct, almost like admitting you aren't paying attention. The softer, more natural move is to give a short reason and trail off.

すみません、少すこし眠ねむくて…。 — Sorry, I'm a bit sleepy... (polite, 眠ねむくて is the て-form connector, and the sentence is left open) 昨日きのうあまり寝ねられなくて、少すこし眠ねむいです。 — I couldn't sleep much yesterday, so I'm a little sleepy. (polite, with the reason first)

Giving the reason first and using くて to leave the sentence hanging is what a native speaker would do. It turns a confession into a small apology.

How does it sound in anime?

Anime loves sleepiness because it is cute and easy to show. You will hear the stretched casual forms, a yawn, and a trailing-off sentence.

ふわぁ…眠ねむい…。 — Yawn... I'm sleepy... (casual, the ふわぁ is the yawn, written out as a sound) まだ眠ねむいよ…あと5分ふん…。 — I'm still sleepy... five more minutes... (casual, a classic morning scene) 眠ねむそうだね、昨日きのう夜更よふかししたの? — You look sleepy, did you stay up late? (casual, 眠ねむそう used for the other person)

If you hear ねみぃ or ねみー, it is a rougher, sleepier voice, usually a character who is relaxed with the person they are talking to.

Common mistakes

  • Saying 彼かれは眠ねむい about someone else. It sounds like you are reading his mind. Use 眠ねむそう, 眠ねむいみたい, or 眠ねむいらしい.
  • Using 眠ねむい when you mean 疲つかれた. If your body is worn out but you are not drowsy, 疲つかれた is the word.
  • Using 寝ねる for "sleepy". 寝ねる is a verb. 寝ねい is not a word. For the feeling, it is always 眠ねむい.
  • Using ねみー with a teacher or boss. It is fine among close friends but too rough for most other places.
  • Forgetting that 眠ねむくなる is a change. 眠ねむくなった means "I got sleepy," not "I am sleepy right now" — that is 眠ねむい.

Practice

Build each answer before opening it. Questions 4 and 5 are a pair, and so are 6 and 7.

1. Say "I'm sleepy" politely.

Show answer

眠ねむいです — 眠ねむい is an i-adjective, and です makes it polite.

2. Say "I'm not sleepy at all" in casual Japanese.

Show answer

全然ぜんぜん眠ねむくない — 眠ねむい becomes 眠ねむくない, and 全然ぜんぜん pairs with a negative.

3. What is the difference between 眠ねむい and 眠ねむくなる?

Show answer

眠ねむい is the state; 眠ねむくなる is the change into it. 眠ねむくなってきた means the sleepiness is creeping in.

4. You see your friend yawning. Say "He looks sleepy."

Show answer

彼かれ、眠ねむそうだね — そう marks a judgment from what you can see, which is natural for other people.

5. Say "He is sleepy" as a flat statement, then explain why it sounds odd.

Show answer

彼かれは眠ねむい sounds odd because you are stating someone else's inner feeling as if you could feel it. That is why 眠ねむそう, 眠ねむいみたい or 眠ねむいらしい are used instead.

6. You are exhausted from a long day, but you can't sleep. Which word fits: 疲つかれた or 眠ねむい?

Show answer

疲つかれた — your body is worn out, but you are not drowsy.

7. You slept only three hours and keep nodding off. Which word fits: 疲つかれた or 眠ねむい?

Show answer

眠ねむい — the feeling is about wanting to sleep, not about being worn out.

8. What does 眠気ねむけ覚さまし mean, and what is the noun 眠気ねむけ?

Show answer

眠気ねむけ is sleepiness; 眠気ねむけ覚さまし is something that wakes you up, like coffee. 覚さます means to wake or bring back to alertness.

9. You are in a meeting and want to admit you are drowsy politely. What is a softer way than 眠ねむいです?

Show answer

すみません、少すこし眠ねむくて… — the て-form leaves the sentence open, which sounds like a small apology instead of a flat statement.

10. Which means "dozing off lightly": うとうと or ぐっすり?

Show answer

うとうと — it is half asleep. ぐっすり describes deep, sound sleep.

Use a trial lesson to say 眠ねむいです politely, describe a sleepy-looking friend with 眠ねむそう, and talk about what you do about 眠気ねむけ.

FAQ

Is 眠ねむい written in kanji or hiragana? Both are common. 眠ねむい is the standard kanji spelling, and ねむい in hiragana is fine in casual writing, messages and beginner materials.

What is the difference between 眠ねむい and 眠ねぶたい? Both mean sleepy. 眠ねぶたい is softer and can sound a little childlike. 眠ねむい is neutral and safe in most situations.

How do I say "I want to sleep"? Use 寝ねたい (ねたい), the want-form of 寝ねる: 早はやく寝ねたい means "I want to go to bed soon." It is about wanting to sleep, while 眠ねむい is about feeling sleepy right now.

Can I say 眠ねむいです to my teacher? Yes, it is grammatically polite. But 少すこし眠ねむくて… with a reason sounds more natural and less blunt if you are in a lesson or a meeting.

Is ねみー rude? Not rude, just very casual and a bit rough. Use it with close friends, not with people you owe politeness.

How do you say "sleepy" in Japanese in a way that sounds cute? Stretch it: ねむー, or add a gentle ending: 眠ねむいなあ. Anime characters often add a yawn like ふわぁ before it.

Vocabulary from this article

Tap the block to select all of it, then copy. In Anki: File → Import, note type Basic, separator Tab — the first column becomes the front, the second the back.

眠い	ねむい — sleepy
眠たい	ねむたい — sleepy (softer)
眠くなる	ねむくなる — to get sleepy
眠そう	ねむそう — looks sleepy
眠気	ねむけ — sleepiness, drowsiness
眠気覚まし	ねむけざまし — something that wakes you up
寝不足	ねぶそく — lack of sleep
うとうと	うとうと — dozing, half asleep
ぐっすり	ぐっすり — sleeping soundly
寝る	ねる — to go to bed, to sleep
眠る	ねむる — to be asleep
疲れた	つかれた — tired
夜更かし	よふかし — staying up late
我慢する	がまんする — to endure, to hold back

I'm Yuuki, a Japanese teacher based in Tokyo. I've taught on italki as a Top 1% teacher and watched over 1,500 anime, so most of the example sentences on this blog come from lines I've actually heard students ask about — including this one, which comes up in almost every beginner's first weeks. For practice with feedback, Book a trial lesson · $13, or work through Japanese practice exercises first.

Sources: the author's own lessons and standard reference grammars.

More drills like the ones above, plus a timed JLPT-style mock test: Practice · N5 · Read something at this level: JLPT N5 stories with audio

More “Describing Things: Japanese Adjectives & Opposites” articles →

Want to try this in a real conversation?

30-minute trial lesson, $13. Times shown in your own timezone.

Practice it out loud with a Tokyo native. ★5.0 from 358 italki reviews.

See how the lessons work →

Book a trial lesson · $13