treachery

noun

Etymology: From Middle English trecherie, from Old French tricherie, trecherie, from tricher, trichier (“to cheat”).

1. Deliberate, often calculated, disregard for trust or faith.

   “Suddenly, in the midst of high-camp treachery and sleuthery, each character does a star turn, breaking out in song.”

2. The act of violating the confidence of another, usually for personal gain.
3. Treason.
4. An act or instance of treachery.

   “These submerged treacheries left an atmosphere. Even two such practised obliterators of their species as Bradly and Podson could not fail to note that each was secreting a certain reservation of opinion on the other.”