Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
furtĭfĭcus, a, um, adj. [furtum-facio], that commits theft, thievish: minus jam furtificus sum quam antehac: rapio propalam, Plaut. Ep. 1, 1, 10: manus, id. Ps. 3, 2, 97: laeva, id. Pers. 2, 2, 44.