Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
‡ căballārĭus, i, m. [caballus], = κέλης, ίππεύς, a rider, horseman, Gloss. Lat. Gr.: ίπποκόμος (i.e. a hostler) caballarius, Gloss. Vet.; hence, Ital. cavaliero, Fr. chevalier.