Lewis Short
impĕrātus | inp- (noun M) : (), , impero
* A command, order (post-Aug. and very rare), Ambros. de Fuga Saec. 2, 8: ACILII GLABRIONIS IMPERATV,Inscr. Orell. 1525: imperatu Gratiani,Amm. 31, 7, 4.
Charlton T. Lewis, Charles Short, A Latin Dictionary