I.a lie, untruth, falsehood.
I. Lit. (class.): “dicere alicui mendacium de re aliquā,” Plaut. Bacch. 4, 9, 33: “mendacio fallere,” Cic. Mur. 30, 62: “vatum,” Ov. F. 6, 253: “famae,” id. ib. 4, 311: “immensa spirant mendacia,” Juv. 7, 111: “Titiae meae, cum quā sine mendacio vixi,” i. e. honestly, without hypocrisy, Dig. 34, 2, 36: “prophetāsti mendacium,” Vulg. Jer. 20, 6; cf. id. ib. 27, 10: “credere mendacio,” to believe a lie, id. 2 Thess. 2, 11.—
B. Esp., a fable, fiction (opp. historic truth): “poëtarum,” Curt. 3, 1, 4.—
II. Transf., of things, a counterfeit (post-Aug.): “neque est imitabilior alia mendacio vitri,” Plin. 37, 8, 33, § 112; 35, 6, 29, § 48.