Lewis & Short

Ē̆sāĭās, ae, m. [Heb.], the Jewish prophet Isaian, Lact. 4, 11, 10; Prud. στεφ. 5, 524.
Hence, Ēsāĭānus, a, um, adj., of Isaiah, Sulp. Sev. Ep. 2, 10.