What does boo mean?
'Boo' is an exclamation of disapproval or scorn, most familiarly heard when audiences voice their displeasure with a performance, a speech, or a decision on the playing field. It functions as an interjection ('Boo!'), as a noun for the cry itself or a chorus of such cries, and as a verb meaning to direct that sound at someone. Though overwhelmingly negative in this sense, the same syllable has an entirely benign second life as a playful device for startling people, beloved of children and Halloween pranksters alike. In modern slang, 'boo' has further evolved into a term of endearment for a romantic partner. Loud, unmistakable, and impossible to ignore, the boo remains one of the oldest forms of audience feedback — a spontaneous, collective judgment delivered without a single written word.
An exclamation used to express disapproval or scorn, or playfully to startle someone.
"'Boo!' shouted the crowd as the unpopular decision was announced."
A cry of 'boo', especially one expressing an audience's disapproval.
"His speech was greeted by a mixture of cheers and boos."
To shout 'boo' at someone, especially a performer, in derision or rejection.
"The audience booed the singer off the stage."
Standard plural, used mainly of cries from a crowd.
"The announcement was met with loud boos from the stands."
Roman crowds jeered failing performers in the arena — today's stadium boo is an ancient tradition of instant audience review that no bad act has ever escaped.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of boo
'Boo' entered English usage in the late eighteenth century, first attested around the 1790s as a theatrical heckling cry, though it likely descends from older imitative exclamations used to startle or drive away. It appears to be an expressive formation rather than a borrowing, related in spirit to other vocal interjections. Its affectionate slang use ('my boo') traces separately to the French 'beau'.
Related word forms
How boo is actually used
As an exclamation, 'boo!' is also used informally and playfully to startle someone, especially around Halloween; this playful sense carries no hostility. Booing a performer or official, by contrast, is openly hostile and considered rude in most settings. The word is informal in all senses.
Easily confused with boo
Lowercase 'boo' as an exclamation of disapproval differs from the affectionate slang term 'Boo' used for a sweetheart, which derives from the French 'beau'.