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

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

Perfidy — from the French perfidie via the Latin perfidia — means deceitfulness, treachery or a breach of faith or promise. —Harmeet Kaur, CNN Money, 21 Jan. 2026

But despite all this, not every Chelsea fan outside his family will regard this transfer as treachery. —Simon Johnson, New York Times, 17 Jan. 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