Treachery is a betrayal of trust.(noun)
An example of treachery is when you cheat on your wife with her best friend.
See treachery in Webster's New World College Dictionary
noun pl. treacheries
Origin: ME trecherie < OFr tricherie, trickery < trichier, to cheat: see trick
See treachery in American Heritage Dictionary 4
noun pl. treach·er·ies
Origin: Middle English trecherie
Origin: , from Old French
Origin: , from trichier, to trick
Origin: , probably from Vulgar Latin *triccāre; see trick.
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