The meaning of PERFIDY is the quality or state of being faithless or disloyal : treachery. How to use perfidy in a sentence.

Perfidy constitutes a breach of the laws of war and is a war crime, as it degrades the protections and mutual restraints developed in the interest of all parties, combatants and civilians.

PERFIDY definition: deliberate breach of faith or trust; faithlessness; treachery. See examples of perfidy used in a sentence.

PERFIDY definition: 1. behaviour that is not loyal 2. behavior that is not loyal. Learn more.

Definition of perfidy noun in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

Dec 14, 2025 · Noun perfidy (countable and uncountable, plural perfidies) A state or act of violating faith or allegiance; violation of a promise or vow, or of trust. Synonyms: betrayal, …

10 hours ago · Defense What is perfidy? Report accuses US of using disguised plane in boat attack by Addy Bink - 01/13/26 4:03 PM ET