Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
montĭ-văgus, a, um, adj. [mons-vagus], mountain-roaming, that wanders over mountains (mostly poet.): Diana, Stat. Ach. 1, 450: fera, Lucr. 1, 404: genus ferarum, id. 2, 597; 1081: ac silvestres cursus lustrationesque, Cic. Tusc. 5, 27, 79.