Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
† hippŏcentaurus, i, m., = ἱπποκέϝταυπος, a fabulous creature, half horse and half man, hippocentaur, Cic. N. D. 2, 2, 5; id. Tusc. 1, 37, 90; Plin. 7, 3, 3, § 35: si quis rem quae in rerum natura non est aut esse non potest, velut hippocentaurum stipuletur, Gai. Inst. 3, 97 a.