Lewis & Short

Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.

perfĭdus, a, um, adj. [per-fides], that breaks his promise, faithless, false, dishonest, treacherous, perfidious.

  1. 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.
          1. (β) With gen. (poet.): gens perfida pacti, faithless, Sil. 1, 5.
        1. 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.
        2. 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.
  2. 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.