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Synonyms

boo

1 American  
[boo] / bu /

interjection

  1. (used to express contempt or disapprobation or to startle or frighten.)

noun

plural

boos

  1. an exclamation of contempt or disapproval.

    a loud boo from the bleachers.

verb (used without object)

booed, booing

  1. to cry boo in derision.

verb (used with object)

booed, booing

  1. to show disapproval of by booing.

boo 2 American  
[boo, boh] / bu, boʊ /

noun

  1. Slang. marijuana.

boo 3 American  
[boo] / bu /

noun

Slang.

  1. one's boyfriend or girlfriend.

boo British  
/ buː /

interjection

  1. an exclamation uttered to startle or surprise someone, esp a child

  2. a shout uttered to express disgust, dissatisfaction, or contempt, esp at a theatrical production, political meeting, etc

  3. is extremely timid or diffident

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

verb

  1. to shout "boo" at (someone or something), esp as an expression of disgust, dissatisfaction, or disapproval

    to boo the actors
"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Usage

What else does boo mean? Boo is the sound we pretend ghosts make as well as a sound we make when we really don’t like something. Boo is also an affectionate term for one's significant other, similar to bae.

Etymology

Origin of boo1

First recorded in 1630–40; expressive formation

Origin of boo2

First recorded in 1955–60; of uncertain origin

Origin of boo3

1985–90; of uncertain origin; possibly an alteration of French beau “boyfriend, admirer”

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

The alternative is to mope and boo and there's no future in that.

From BBC • Mar. 31, 2026

Because more than 75,000 of them came to cheer the local team and boo the visiting one, no matter who was wearing that bright pink uniform.

From Los Angeles Times • Feb. 24, 2026

Why do we boo in the first place?

From BBC • Feb. 13, 2026

"The stadium will boo me, I'm used to it, I certainly hope they do -- maybe it will take the pressure off other players," Ronaldo told a news conference Wednesday.

From Barron's • Nov. 12, 2025

I say as my classmates boo and shout.

From "On the Come Up" by Angie Thomas

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.