Dictionary.com
Thesaurus.com
Synonyms

traitor

American  
[trey-ter] / ˈtreɪ tər /

noun

  1. a person who betrays another person, a cause, or any trust.

  2. a person who commits treason by betraying their country.


traitor British  
/ ˈtreɪtə /

noun

  1. a person who is guilty of treason or treachery, in betraying friends, country, a cause or trust, etc

"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

Other Word Forms

  • traitorous adjective
  • traitorously adverb
  • traitorship noun
  • traitress noun

Etymology

Origin of traitor

First recorded in 1175–1225; Middle English from Old French from Latin trāditōr-, stem of trāditor “betrayer”; traditor

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.

And, in killing Capt. Mayer, he underscored the idea that the traitor was inside the army—a concept that obviously was key in the Dreyfus affair.

From Slate • Mar. 2, 2026

"But if he is a traitor, he doesn't deserve it," Walesa added, arguing that for the moment, "it's too early to judge".

From Barron's • Feb. 23, 2026

We're introduced to Roth's rather official-looking English gentleman officer character who asks Duke Shelby - in secret - if he is willing to become a traitor.

From BBC • Feb. 19, 2026

“I think it’s time that we abandon this disrespectful word malinchista to refer to someone as a traitor to Mexico,” said Roberto Pineda, 61, a cafe owner who enjoyed the spectacle.

From Los Angeles Times • Jan. 25, 2026

There had to be a link between Hugo being a traitor and Will’s disappearance – and maybe Hannie’s, too.

From "Code Name Kingfisher" by Liz Kessler