perfidy

thumb|The use of the Trojan Horse by the Greeks in the [[Trojan War has been described by modern sources as an ancient example of perfidy.]]

In the context of war, perfidy is a form of deceptive tactic where one side pretends to act in good faith, such as signaling a truce (e.g., raising a white flag), but does so with the deliberate intention of breaking that promise. The goal is to trick the enemy into lowering its guard, such as stepping out of cover to accept a supposed surrender, only to exploit its vulnerability.