Treachery
Origin
From Middle English trecherie, from Old French tricherie, trecherie, from tricher, trichier ("to cheat"), from Middle Dutch trek ("a trick"), from trekken ("to draw, play a trick on"). More at trick.
Full definition of treachery
Noun
treachery
(plural treacheries)- Deliberate, often calculated, disregard for trust or faith.
- The act of violating the confidence of another, usually for personal gain.
- Treason.