Perfidy
The state of being deceitful and untrustworthy. Perfidy is a war crime, as under international humanitarian law (ihl), which governs how armies may wage war, it is illegal to kill or wound “treacherously”. Specifically, that covers “acts inviting the confidence of an adversary to lead him to believe that he is entitled to…protection”. This is distinct from classical military deception. The classic example of perfidy is feigning surrender. If you wave a white flag and then pull out a gun as the enemy approaches to take you prisoner, that is a straightforward breach of the law.
Perfidy also includes a number of other acts. Soldiers cannot use the uniforms or signs of United Nations peacekeepers or those of neutral countries. They cannot pretend to be wounded to lull the enemy into approaching or simulate the “distinctive emblem of cultural property”, for instance, disguising a command post as a mosque. Air forces can broadcast transponder signals that make their planes look like enemy ones—which enjoy no special protection—but they cannot pretend to be medical transports or send distress signals.