闷
mēn , mèn · HSK 7
stuffy
🚪 门 door + 心 heart: a heart shut behind a closed door feels stuffy and smothered
Sound-alike: mèn is like a muffled men hum behind a sealed door. The 门 gate up top traps the 心 heart below, so the air and the mood both turn close, stuffy, and shut-in.
闷 — door 門 + heart 心
A semantic compound: 心 (heart) enclosed by 門 (door) depicts a heart shut behind a closed door, evoking stuffiness and depression. Read mēn it means stuffy or airless; read mèn it means bored, depressed, or sealed up tight.