impotent(lacking in power, as to act effectively; helpless) adjective [UK: ˈɪm.pə.tənt] [US: ˈɪm.pə.tənt]I've become impotent. = Sono diventato impotente.
powerless(lacking sufficient power or strength) adjective [UK: ˈpaʊə.lɪs] [US: ˈpaʊər.ləs]John is powerless. = John è impotente.