Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† ŏnŏcentaurus, i, m., = ὀνοκένταυρος, an ass-centaur, a fabulous animal, Isid. Orig. 11, 3, 39: et occurrent daemonia onocentauris, Vulg. Isa. 34, 14.
Transf., of an impure person, Hier. in Isa. 6, 13, 22.