Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Hēphaestĭo, ōnis, m., = Ἡφαιστίων, a favorite of Alexander the Great, and one of his generals, Curt. 3, 12, 9; 4, 16, 16; Nep. Eum. 2.