To make loud disapproving sounds or shout 'boo' to show dislike or to try to frighten someone.
From the interjection 'boo,' which is onomatopoetic—it imitates the sound itself. Became common as a verb in the 19th century during theatrical performances.
When audiences started booing performers in the 1800s, opera houses saw it as a revolutionary act—for the first time, common people could publicly reject the entertainment of the rich by literally drowning them out with noise.
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