treachery

noun

treach·​ery ˈtre-chə-rē 

ˈtrech-rē

plural treacheries

1

: violation of allegiance or of faith and confidence : treason

2

: an act of perfidy or treason

Synonyms of treachery

• betrayal
• treason

Examples of treachery in a Sentence

a tale of treachery and revenge

was furious that she revealed his secret and never forgave her for the treachery

Recent Examples on the Web

After Thomas Hickey was hanged that year for mutiny, sedition and treachery, Washington warned that his fate should serve as a caution to all soldiers. —Kim Hjelmgaard, USA Today, 26 Feb. 2026

With their leader detained, El Mayo’s sicarios, or hit men, declared war against supporters of Chapo’s sons in an attempt to exact vengeance for the treachery and strengthen their own position in the wider organization. —Daniel Depetris, Mercury News, 26 Feb. 2026

With their leader detained, El Mayo’s sicarios, or hit men, declared war against supporters of Chapo’s sons in an attempt to exact vengeance for the treachery and strengthen their own position in the wider organization. —Daniel Depetris, Chicago Tribune, 24 Feb. 2026

This whole thing — Yasmin’s treachery, Harper’s ruthlessness, Ed’s heel turn, Lisa’s demise — is about the idea of an audit. —Amanda Whiting, Vulture, 23 Feb. 2026

Word History

Etymology

Middle English trecherie, from Anglo-French, from trecher, tricher to deceive, from Vulgar Latin *triccare — more at trick entry 1

First Known Use

13th century, in the meaning defined at sense 1

Rhymes for treachery

• lechery

Kids Definition

treachery

noun

treach·​ery ˈtrech-(ə-)rē 

plural treacheries

1

: violation of allegiance or of faith and confidence : treason

2

: an act of treason