Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
terrĭfĭcus, a, um, adj. [terreo-facio], that causes terror, frightful, terrific (poet.): (Curetes) cristae, Lucr. 2, 632; 5, 1314: caesaries capitis, Ov. M. 1, 179: vates, Verg. A. 5, 524: sacrum, Val. Fl. 1, 785: vaticinationes, Plin. Ep. 6, 20, 19.