having the capability of starting, operating, moving, etc., independently

an automatic sprinkler system; an automatic car wash.

Physiology . occurring independently of volition, as certain muscular actions; involuntary.

done unconsciously or from force of habit; mechanical

an automatic application of the brakes.

occurring spontaneously

automatic enthusiasm.

(of a firearm, pistol, etc.) utilizing the recoil or part of the force of the explosive to eject the spent cartridge shell, introduce a new cartridge, cock the arm, and fire it repeatedly.

a machine that operates automatically.

automatic rifle.

automatic pistol.

Football . audible ( def. 2 ) .

automatic pilot.

automatic transmission.

an automobile equipped with automatic transmission. ?

on automatic

being operated or controlled by or as if by an automatic device.

adjective

by hand , manual , thought-out , stilted , unnatural

adjective

automated , electric , electronic , mechanical , mechanized , motorized , robotic , self-moving , self-regulating , self-starting , autogenetic , habitual , impulsive , instinctive , instinctual , intuitive , involuntary , knee-jerk , natural , perfunctory , reflex , routine , spontaneous , unconscious , unforced , unintentional , unmeditated , unthinking , unwilled , assured , certain , inescapable , inevitable , necessary , unavoidable , unpremeditated , accidental , automatous , kneejerk , predictable , self-propelling