1. n. a hired gunman; a bodyguard, an assassin, or a member of a gang of criminals. (Underworld and Western.) Willie and his guns came by to remind Gary of what he owed Mr. Gutman.
2. n. a leader; the key member of a group. Who’s the gun around here?
3. tv. to race an engine; to rev up an engine. See how loud it is when I gun it?