perfĭdĭa, ae, f. [perfidus],
faithlessness , dishonesty , treachery , falsehood , perfidy (class.): perfidiā deceptus, Cic. Rosc. Am. 38, 110: fraude et perfidiā aliquem fallere, id. ib. 40, 117; id. Fam. 1, 2, 3: admittere perfidiam in aliquem, Suet. Caes. 75: perfidiae tantae (fuit), ut, etc., id. Ner. 5: repens, Tac. H. 4, 25; Juv. 13, 24.—In plur., Plaut. Capt. 3, 3, 7; id. Ps. 2, 1, 6; Gell. 14, 2, 6.—Of an inanim. thing: sub ipsis positum labris in acoris perfidiam vinum repente mutari, Arn. 1, 12.