寝不足（ねぶそく、nebusoku）
- lack of sleep

The Japanese word 寝不足 (ねぶそく) means "lack of sleep", "sleep deprivation", or "not getting enough sleep". It describes the state of being tired or feeling unwell due to insufficient rest. It refers to the condition resulting from not having had adequate sleep.

⚫︎最近、寝不足で集中できない。 Translation: Recently, I can't concentrate because I haven't been getting enough sleep. ⚫︎試験前で、寝不足の人ばかりだ。 Translation: Before the exam, everyone is sleep-deprived. ⚫︎寝不足が原因で頭痛がする。 Translation: Headaches are caused by寝不足 (lack of sleep).

⚫︎ You can use 寝不足 when talking about yourself or others who haven't slept enough. ⚫︎ It is a common word in daily conversation, used when discussing tiredness, difficulties concentrating, or any problems related to a lack of sleep. ⚫︎ Use it to describe the condition of being tired due to not sleeping enough, or the effects of not sleeping enough.

⚫︎ 寝不足 is usually written in kanji and hiragana. ⚫︎ Kanji: 寝不足 ⚫︎ Hiragana: ねぶそく ⚫︎ It's also acceptable, though less common, to write it entirely in hiragana (ねぶそく). ⚫︎ There are no significant variations in the okurigana.

⚫︎ 睡眠不足 (すいみんぶそく) - lack of sleep ⚫︎ 眠い (ねむい) - sleepy ⚫︎ 疲れやすい (つかれやすい) - easily tired

⚫︎ 熟睡 (じゅくすい) - sound sleep, sleeping well ⚫︎ 快眠 (かいみん) - good sleep

昨夜は映画を見すぎて、寝不足だった。 ・Translation: I watched too many movies last night, and I didn't get enough sleep. ・Explanation: This sentence explains that the speaker didn't get enough sleep because of watching movies the night before.

試験勉強で寝不足が続いている。 ・Translation: I've been sleep-deprived because of studying for the exam. ・Explanation: This sentence explains the speaker has a continuous state of not getting enough sleep because of study.

The word 寝不足 is formed from: ⚫︎ 寝 (ね) - "sleep" (stem of the verb 寝る, to sleep) ⚫︎ 不足 (ふそく) - "lack", "deficiency", or "insufficient" Therefore, 寝不足 literally means "sleep insufficiency" or "lack of sleep".