perfidy
n//ˈpɜː.fɪ.di//förräderi, perfiditet, svek, trolöshet, förrädiskt förfarande
A state or act of violating faith or allegiance; violation of a promise or vow, or of trust.
(international law, in warfare) An illegitimate act of deception, such as using symbols like the Red Cross or white flag in a false claim of surrender to gain proximity to an enemy for purposes of attack.