I.that breaks his promise, faithless, false, dishonest, treacherous, perfidious.
I. Lit. (class.; “syn. infidus): vanum et perfidiosum esse,” Cic. Quint. 6, 26: “omnes, aliud agentes, aliud simulantes, perfidi, improbi, malitiosi sunt,” id. Off. 3, 14, 60.—
b. Of inanim. and abstr. things (poet.): “bella,” Sil. 15, 819: “nex,” effected by treachery, Sen. Agam. 887: “arma,” Ov. F. 4, 380: “verba,” id. R. Am. 722.—
c. Adverb.: perfidum ridens Venus (= maligne ac dolose), Hor. C. 3, 27, 67.—As subst.: perfĭdus , i, m., a scoundrel, Juv. 13, 245; 9, 82.—
II. Transf., treacherous, unsafe, dangerous (poet. and in post-class. prose): “freta,” Sen. Med. 302: “saxa,” id. Agam. 570: “perfidum glacie flumen,” Flor. 3, 4, 5: “perfida et lubrica via,” Prop. 4 (5), 4, 49. “vappa,” wretched wine that has a good appearance, Mart. 12, 48, 14.—Sup.: “homo, quoad vixerat, perfidissimus,” Amm. 16, 12, 25.—Adv.: perfĭ-dē , faithlessly, perfidiously, treacherously (post-Aug.): “perfide recuperans,” Sen. Contr. 4, 26: “rumpere pactum,” Gell. 20, 1, 54: “agere,” Dig. 26, 7, 55: “quod perfide gestum est,” ib. 44, 4, 4, § 13.