A worrywart is someone who worries about small things that do not deserve it — the light left on, whether the door is locked, whether the plane will be late. The 'unimportant' part is what separates it from 'worrier'. It is teasing, informal, and affectionate; you say it to a friend, a spouse, a parent. Said to a stranger it would be rude. It is a much more American word than British — Americans use it freely, while British speakers more often say 'worrier' or the old slang 'worryguts'. In Taiwan you are most likely to meet it in American films and TV. The most common frames are 'don't be such a worrywart' and 'you're such a worrywart'. Where does the strange 'wart' come from? A wart is the small hard lump you get on your skin — but here it is chosen mostly for the sound, the matching w- at the start of both halves, the same way English enjoys 'namby-pamby' or 'wishy-washy'. It goes back to a newspaper comic strip character in the 1920s and 30s and became general slang by the 1950s. Spelling varies a little in print — worrywart, worry-wart, worry wart — but one word is now standard.

愛瞎操心的人、雜念很多的人；台灣可說「操心命」「什麼都要煩」。語氣是開玩笑、親暱的，對朋友家人講可以，對不熟的人講會失禮。美式用語。