Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
Belĭal, indecl. (Belĭas, ae, m.), = Heb. [??], Belial, a chief of the evil spirits, Prud. Psych. 714; Tert. Cult. Fem. 1, 2; Vulg. Deut. 13, 13; id. 2 Cor. 6, 15.