- 1a sound that people make to show that they do not like an actor, speaker, etc. ‘Boo!’ they shouted, ‘Get off!’ The speech was greeted with loud boos from the audience. boos and hisses from the crowd
- 2people shout Boo!when they want to surprise or frighten somebody More Like This Exclamations aargh, ah, aha, ahchoo, ahem, aw, bah, boo, coo, d’oh, eek, eh, er, eww, gee, ha, hey, ho ho, ho-hum, hooray, huh, mm, oh, oho, oi, ooh, oops, ouch, ow, oy, pah, phew, psst, sh, tsk tsk, tut, ugh, uh, uh-uh, uh-oh, um, whoopee, whoops, woo hoo, wow, yay, yippee, yuck, yumSee worksheet. Word Origin early 19th cent.: imitative of the lowing of oxen (the sound was considered to be derisive); compare with hiss and hoot.Idioms
to be very shy or gentle He's so nervous he wouldn't say boo to a goose.