gun

noun

1
the discharge of a firearm as signal or as a salute in military ceremonies
two runners started before the gun
a twenty gun salute
2
a pedal that controls the throttle valve
he stepped on the gas
3
large but transportable armament
4
a hand-operated pump that resembles a revolver; forces grease into parts of a machine
5
a weapon that discharges a missile at high velocity (especially from a metal tube or barrel)
6
a professional killer who uses a gun
7
a person who shoots a gun (as regards their ability)

Also useful for “gun”:Unscrambler— Turn loose letters into real words