perfĭdĭa (noun 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.

s. TLL