To fight to no purpose, or against an imaginary enemy.

(medicine) The sensation of inadequate inspiration that typically results in an increased respiratory drive, and deep, rapid and laboured breathing.

(archaic) compressed air

A motor that does mechanical work by expanding compressed air.

plural of air motor

To be ecstatic.

That portion of air which cannot be expelled by the most violent efforts from the lungs.

plural of air engine

An engine put into motion by air expanded by heat.

(American football) An offensive scheme developed by NFL coach Don Coryell.