Dictionary.com
Thesaurus.com
Synonyms

boo

1 American  
[boo] / bu /

interjection

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


noun

boos plural
  1. an exclamation of contempt or disapproval.

    a loud boo from the bleachers.

verb (used without object)

boos, present (3rd person singular) booed, past participle, past booing present participle
  1. to cry boo in derision.

verb (used with object)

boos, present (3rd person singular) booed, past participle, past booing present participle
  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.

Other Word Forms

Inflected Forms

Nouns

Participles

Conjugated Forms

Present

Past

Future

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.

It seemed the match was going to be easier for the Mexicans with South Africa short-handed, but fans began to boo the Mexican players after they stopped attacking and appeared nervous.

From Los Angeles Times • Jun. 12, 2026

Perhaps the organizers thought the crowd wouldn’t dare boo during a patriotic hymn.

From Salon • Jun. 11, 2026

They grads are also primed to boo any speakers who so much as mutter the words “artificial intelligence.”

From Slate • May 20, 2026

“They wouldn’t boo me,” Wrobleski said, “if they didn’t know who I was.”

From Los Angeles Times • Apr. 7, 2026

Warning: Your teacher is about to gather you, boo.

From "On the Come Up" by Angie Thomas

Vocabulary.com logo
by dictionary.com

Look it up. Learn it forever.

Remember "boo" for good with VocabTrainer. Expand your vocabulary effortlessly with personalized learning tools that adapt to your goals.

Take me to Vocabulary.com