1.A device designed to rapidly cover a surface with paint by ejecting a spray of paint from a reservoir onto the surface by means of compressed air or other special mechanism. Also called a paint sprayer. Use of a paint gun is an efficient method to rapidly paint large surface areas.
2.A device resembling a rifle, designed to shoot a small quantity of paint at an opponent as part of a game often conducted at specially-designed indoor locations, or outdoors. Points are awarded to players who hit their target; success in hitting one's target is made obvious by the appearance of a spot of paint on the player who is hit.