Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
mātrimus (the quantity of the i is doubtful), a, um, (collat. form: matrimes ac patrimes dicuntur, quibus matres et patres adhuc vivunt, Paul. ex Fest. p. 126 Müll.), adj. [mater], that has a mother living: decem ingenui, decem virgines, patrimi omnes matrimique, Liv. 37, 3, 6; Auct. Har. Resp. 11; Tac. H. 4, 53; Macr. S. 1, 6, 13; Lampr. Heliog. 8; Vop. Aur. 19; Gell. 1, 12, 2; cf. patrimus.