Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
pĕcūlĭārĭus, a, um, adj. [peculium], of or relating to private property (post-class. for the class. peculiaris): res, Dig. 44, 4, 4: causa, ib. 15, 1, 4 fin. (al. peculiari); Inscr. Murat. 1640, 7: peculium peculiarius, Not. Tir.