Blindfire is when a person fires a weapon from behind an object and does not reveal themself. While performing this, the person usually does not know where he is aiming and is thus shooting "blindly".

The name also is used in paintball

Paintball

Paintball is a sport in which players compete, in teams or individually, to eliminate opponents by tagging them with capsules containing water soluble dye and gelatin shell outside propelled from a device called a paintball marker . Paintballs have a non-toxic, biodegradable, water soluble...

 and airsoft

Airsoft

Airsoft is a sport in which participants shoot round non-metallic pellets launched via replica firearms.Gameplay varies in style and composition but often range from short-term skirmishes, organized scenarios, military simulations, historical reenactments, to competition target shooting events...

, and is usually an illegal move due to possibly unnecessary injuries

Injury

-By cause:*Traumatic injury, a body wound or shock produced by sudden physical injury, as from violence or accident*Other injuries from external physical causes, such as radiation injury, burn injury or frostbite*Injury from infection...

.

A common misconception is that it is an effective way to provide cover fire for an advancing team/squad

Team

A team comprises a group of people or animals linked in a common purpose. Teams are especially appropriate for conducting tasks that are high in complexity and have many interdependent subtasks.A group in itself does not necessarily constitute a team...

 mate, however, the point of cover fire is to suppress, but not necessarily kill, the enemy defending a position.