Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
possessīvus, a, um, adj. [possideo], of or relating to possession, possessive; a gram. t. t. (post-Aug.): nomina (e. g. Ciceronianus, Evandrius), Charis. p. 128 P. and A.: pronomina (e. g. meus, tuus, suus), Quint. 1, 5, 45: casus, the possessive or genitive case, Prisc. p. 670 P.