Perfidy
Part of speech: noun
Definition: A state of act of violating faith or allegiance; violation of a promise or vow, or of trust reposed; faithlessness; treachery. Specifically, in warfare, an illegitimate act of deception, such as using symbols like the Red Cross or white flag to gain proximity to an enemy for purposes of attack. A state or act of deceit.
Betrayal
Part of speech: noun
Definition: the act of betraying
Example sentence: We have to distrust each other. It is our only defense against betrayal.