Yours, Etc.: Origins and Uses of 8 Sign-Offs
late 14c., "status of a citizen," from Old French civilite (14c.), from Latin civitatem (nominative civitas) "the art of governing; courteousness," from cvilis "relating to a citizen, relating to public life, befitting a citizen; popular, affable, courteous" (see civil). Later especially "good citizenship" (1530s). Also "state of being civilized" (1540s); "behavior proper to civilized persons" (1560s).