n. pl. per·fi·dies 1. Deliberate breach of faith; calculated violation of trust; treachery: "the fink, whose perfidy was equaled only by his gall" (Gilbert Millstein). 2. The act or an instance of treachery. [Latin perfidia, from perfidus, treacherous : per-, to destruction; see PER- + fidēs, faith; see bheidh- in the Appendix of Indo-European roots.] |
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