못 잤어

couldn't sleep

→ 못
phrase Common #4,139
couldn't sleep Informal past-tense form; depending on context, it can mean either being unable to sleep or not getting to sleep.
KO: 어젯밤에 너무 더워서 못 잤어.
EN: I couldn't sleep last night because it was so hot.

어젯밤에 잘 못 잤어?

Did you not sleep well last night?

— 데이 워치 (2006)

나도 못 잤어

I couldn't sleep either.

— 헌팅시즌 (2025)

어젯밤에 잠을 못 잤어

I couldn't sleep last night.

— 내 어머니의 모든 것 (1999)

난 잘 못 잤어

I didn’t sleep well.

— 제5원소 (1997)

잠을 제대로 못 잤어?

Didn't you sleep well?

— 특별한 날 (1977)

그래서 어젯밤에 잠을 못 잤어?

So, you couldn't sleep last night?

— 눈 깜짝할 사이에 (2026)

잠 못 잤어?

Couldn't sleep?

— 가장 따뜻한 색, 블루 (2013)