Illagilsfjallnafnorð hvorugkyn · ÖrnefniFallbeygingarEt.eintalaFt.fleirtalaEintalaNf.nefnifallIllagilsfjallÞf.þolfallIllagilsfjallÞgf.þágufallIllagilsfjalliEf.eignarfallIllagilsfjalls