I.indecl., something contrary to divine law, sinful, unlawful, execrable, abominable, criminal; an impious or wicked deed, a sin, a crime (cf.: scelus, flagitium, peccatum).
I. Lit.: “quicquid non licet, nefas putare debemus,” Cic. Par. 3, 2. 25; cf.: “officia tua mihi nefas est oblivisci,” id. Fam. 15, 21, 5: “Mercurius, quem Aegyptii nefas habent nominare,” id. N. D. 3, 22, 56: nefas est dictu, miseram fuisse talem senectutem, id. Sen. 5, 13: “eum, cui nihil umquam nefas fuit,” id. Mil. 27, 73: “quibus nefas est ... deserere patronos,” Caes. B. G. 7, 40: “corpora viva nefas Stygiā vectare carinā,” Verg. A. 6, 391: “fas atque nefas,” right and wrong, id. G. 1, 505; Hor. Epod. 5, 87; cf. id. C. 1, 18, 10; Ov. M. 6, 585: “per omne fas ac nefas,” in every way, Liv. 6, 14, 10: “nefas triste piare,” Verg. A. 2, 184: “illa dolos dirumque nefas in pectore versat, Certa mori,” id. ib. 4, 563: “lex maculosum edomuit nefas,” i. e. adultery, Hor. C. 4, 5, 22: “in omne nefas se parare,” Ov. M. 6, 613: “summum crede nefas animam praeferre pudori,” Juv. 8, 83: “belli,” civil war, Luc. 2, 507; cf.: “fugiens civile nefas,” id. 7, 432: “magnum nefas contrahere,” Just. 24, 3: “facere nefas,” Vulg. Deut. 22, 21: “operari,” ib. Lev. 20, 13.—Poet., of a wicked person, a wretch, monster: “exstinxisse nefas tamen ... Laudabor (i. e. Helen, as the destroyer of Troy),” Verg. A. 2, 585.—Also inserted as an interjection, O horrid! shocking! dreadful! quātenus, heu nefas! virtutem incolumem odimus, Hor. C. 3, 24, 30; cf.: “heu nefas, heu!” id. ib. 4, 6, 17: “quosne, nefas! omnes infandā in morte reliqui?” Verg. A. 10, 673: “sequiturque, nefas! Aegyptia conjux,” id. ib. 8, 688: “Lavinia virgo Visa, nefas! longis comprendere crinibus ignem,” O horrible! id. ib. 7, 73.—Esp.: “est nefas,” it is forbidden, contrary to law, Varr. L. L. 6, 4. —
II. Poet., transf.
A. A horrible or monstrous thing: “Eumenides Stygiumque nefas,” Luc. 6, 695; 1, 626: “infernum,” id. 7, 170; Stat. Th. 6, 942.—
B. Impossible: levius fit patientiā Quicquid corrigere est nefas, an impossibility (= ἀθέμιτον, ἀδύνατον), Hor. C. 1, 24, 20.