A gun is a hand-held weapon that fires bullets or shells. A hunter's gun looks very different from the gun carried in a holster by a police officer.Guns come in all shapes and sizes, but they are all dangerous weapons.
Most guns are designed to kill or injure, whether when hunting animals or used for self-defense. There are also starting guns, which make a loud noise to mark the start of a race; squirt guns, which fire streams of water; and paintball guns, used to shoot paint pellets during a paintball game. A so-called "hired gun" is a professional who's paid for their particular abilities. "Son of a gun" is an informal, fond way to refer to someone.