Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Perseus.
gnāve, gnāvĭtas, gnāvĭter, gnāvus, v. under nav-.
nāvus (gnāvus), a, um, adj. [Sanscr. gnā, know; Gr. γιγνώσκω; cf. Lat. notus, gnarus; for signif. cf. Germ. kennen and können], busy, diligent, assiduous, active (syn.: impiger, industrius, sedulus; class.): navus repertus homo, Enn. ap. Paul. ex Fest. p. 169 Müll. (Ann. v. 183 Vahl.): homo gnavus et industrius, Cic. Verr. 2, 3, 21, § 53; id. Imp. Pomp. 7, 18: aratores, id. Verr. 2, 3, 51, § 120: filius, id. ib. 2, 3, 69. § 161: vir gnavus, agilis, providus, Vell. 2, 105, 2: rudimenta, Sil. 1, 549: timor, that renders industrious, id. 7, 349.
Comp.: in inquirendis gnaviores quam in componendis, Amm. 26, 4, 4: hostium naviores, Jul. Val. Res Gest. Alex. 1, 41.
Hence, adv., in two forms.