Definition of black ace:
(n) :
Used other than figuratively or idiomatically: see black, ace.
(n) :
(ice hockey) A player from a junior league who is called up by an NHL team after their original team's season has ended and kept as a reserve player.
(n) :
(slang) An elite mafia hitman.
(n) :
(obsolete, euphemistic) A woman's sexual favours, or a woman who gives them.