Treach″er‐y (?), n. [OE. trecherïe, trichere, OF. trecherie, tricherie, F. tricherie trickery, from tricher to cheat, to trick, OF. trichier, trechier; probably of Teutonic origin. See Trickery, Trick.] Violation of allegiance or of faith and confidence; treasonable or perfidious conduct; perfidy; treason.
Be ware, ye lords, of their treachery. Chaucer.
In the council chamber at Edinburgh, he had contracted a deep taint of treachery and corruption. Macaulay.