闹钟
nào zhōng · HSK 4
alarm clock
⏰ 闹 (noisy) + 钟 (clock/bell) = noisy clock
闹 means noisy or to make a racket; 钟 means clock or bell. A 闹钟 is literally a noisy-clock — the clock whose job is to be loud enough to wake you. The 钟 component also shows up in 钟头 (hour) and 时钟 (clock).
闹 — door 门 + market 市
Originally written 鬧, showing 鬥 (fight) over 市 (market) — depicting the clamor of people quarreling in a crowded marketplace. The simplified form replaces 鬥 with 门 (door/gate), keeping the idea of a noisy, bustling space. The core meaning shifted from 'quarrel' to 'noisy, lively, to make a fuss'.
钟 — metal radical 钅 + child 童 (phonetic)
Originally a pictograph of a hanging bell, 钟 is now a semantic-phonetic compound: 钅 (metal) gives the meaning, while 童 hints at the sound. It is the simplified form merging two traditional characters, 鐘 (bell, clock) and 鍾 (cup, to concentrate).