Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
cŏlumbus, i, m. [κόλυμβος; cf.: calvus, color], a male dove or cock-pigeon (and transf., of male persons), Varr. L. L. 9, § 56; Plaut. Rud. 3, 6, 49; Cat. 29, 9; 68, 125; Hor. Ep. 1, 10, 5,