A gun for hire is a person who is hired to use a firearm for a specific job. The term 'gun for hire' is often used to describe a mercenary or a professional assassin. The two crossword solutions for the term GUN FOR HIRE are MERC and THIS, which stand for Mercenary and Hitman, respectively. A mercenary is a soldier who is hired to fight in a foreign army, while a hitman is a professional assassin who is hired to carry out a targeted killing.