noun, plural treach·er·ies.

violation of faith; betrayal of trust; treason.
an act of perfidy, faithlessness, or treason.

Origin of treachery

1175–1225; Middle English trecherie < Middle French, Old French, equivalent to trech(ier) to deceive + -erie -ery

Synonym study

1. See disloyalty.

Antonyms for treachery Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for treachery

Contemporary Examples of treachery

Historical Examples of treachery

  • I should like to meet him face to face, and charge him with his treachery.

    Brave and Bold

    Horatio Alger

  • How could Robert have learned anything of his treachery to his father?

    Brave and Bold

    Horatio Alger

  • He came a little toward the girl who had accused him of treachery.

    Within the Law

    Marvin Dana

  • It was not long before they had to pay a heavy penalty for their treachery and inconstancy.

  • It after wards appears that the scheme of Rumi-naui was one of treachery.

    Apu Ollantay


British Dictionary definitions for treachery


noun plural -eries

the act or an instance of wilful betrayal
the disposition to betray

Word Origin for treachery

C13: from Old French trecherie, from trechier to cheat; compare trick
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

Word Origin and History for treachery

early 13c., from Old French trecherie "deceit, cheating" (12c.), from trechier "to cheat, deceive" (see trick).

Online Etymology Dictionary, © 2010 Douglas Harper