Charlton T. Lewis, Charles Short, A Latin Dictionary

I.perseverance, constancy, in a good sense; and (more freq.) in a bad sense, obstinacy, pertinacity (syn.: perseverantia, pervicacia): dicitur quom demonstratur in quo non debet pertendi et pertendit, pertinaciam esse; “in quo oportet manere, si in eo perstet, perseverantia sit,” Varr. L. L. 5, § 2 Müll.; cf.: “unicuique virtuti finitimum vitium reperietur, ut pertinacia, quae perseverantiae finitima est,” Cic. Inv. 2, 54, 165; v. Att. ap. Non. 432, 32 sq.: “certamen instituit non pertinaciā et studio vincendi, sed, etc.,” Cic. Ac. 1, 12, 44: “desistere pertinaciā,” Caes. B. G. 1, 42: “pertinaciae finem facere,” id. B. C. 3, 10: “muliebri pertinacia accendi,” Tac. H. 4, 56: “pertinaciam alicujus vincere,” id. A. 2, 81.—In a good sense, Liv. 42, 62: “patientia et pertinacia hostis,” Suet. Caes. 68: “in evitando inevitabili malo,” Sen. Q. N. 4, praef. 12: “auctorum pertinacia,” steadfast opinion, Plin. 37, 3, 13, § 52.—Personified, the sister of Æther and Dies, Cic. N. D. 3, 17, 44.