Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
1. Mŏlossus, a, um, adj., = Μολοσσός, of or belonging to the Molossi, Molossian: missi de gente Molossā, Ov. M. 1, 226: canes, famed for their strength, Hor. S. 2, 6, 114: rex, Juv. 12, 108: gladii, id. 14, 162.
Also, subst.: Mŏlossus, i, m.
2. Mŏlossus, i, m., son of Pyrrhus, king of Epirus, and Andromache, the progenitor of the Molossi, acc. to Serv. Verg. A. 3, 297.