Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
trĭbūtārĭus, a, um, adj. [tributum], of or belonging to tribute: necessitas, of paying tribute, Just. 32, 2, 1: solum, subject to tribute, tributary, Plin. 12, 1, 3, § 6; so, praedia tributaria sunt ea, quae in his provinciis sunt, quae propriae Caesaris esse creduntur (opp. stipendiaria), Gai. Inst. 2, 21: civitates, Just. 1, 7, 2: Thraces Macedonum, Flor. 3, 4, 1: tributarius Gallus quidam, Suet. Aug. 40: causa, concerning tribute, Dig. 49, 14, 46: tabellae, letters of credit, Cic. Verr. 2, 4, 66, § 148.