Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
gilbus, v. gilvus.
gilvus (in late Lat. also gilbus; v. the letter B), a, um, adj. [kindr. with Germ. gelb.; Engl. yellow; Sanscr. gāura], pale yellow: equi, Varr. ap. Non. 80, 2; Verg. G. 3, 83; Pall. Mart. 13, 4.