(adj.adv.) : pernix, īcis (abl. pernici, Lucr. 5, 559:
* Pernice,id. 2, 635), adj.per-nitor, qs. striving or pressing through, nimble, brisk, active, agile, quick, swift, fleet (cf.: levis, praepes, celer, promptus): pernix sum manibus,Plaut. Mil. 3, 1, 36: corporum pernicium,Liv. 28, 20; Verg. A. 11, 718: viginti milibus juvenum velocitate pernicibus,Vell. 2, 34, 1: conjugis adventu pernix Saturnus,Verg. G. 3, 93: pernicis uxor Appuli,Hor. Epod. 2, 41: genus,Tac. H. 2, 13: nuntii,id. ib. 3, 40: pedibus celerem et pernicibus alis,Verg. A. 4, 180: temporis pernicissimi celeritas,Sen. Ep. 108, 27: saltus,Plin. 9, 47, 71, § 154.
* With inf.: amata relinquere pernix,Hor. A. P. 165.—Hence, adv.: pernīcĭter, nimbly, quickly, swiftly, Plaut. Am. 5, 1, 63: equo desilire,Liv. 26, 4: exilire,Cat. 61, 8: alites alte perniciterque volantes,Plin. 8, 14, 14, § 36.

s. TLL