(adj.) The characteristic of a firearm being able to fire all rounds in its magazine with a single pull of the trigger.

Note: This characteristic is NOT indicated by the terms assault weapon or semi auto.
Fully automatic firearm types include machine guns, sub-machine guns, assault rifles, and others. Some of these may also have a semi auto mode that can be selected.

"My UZI is a fully automatic firearm, and as such was already illegal before the 1994 Assault Weapons Ban, which banned semi auto rifles."
by ed July 26, 2004
A word made up by liberals to make guns sound scarier and is not a thing. Full and semi are two completely different words
Those gosh darn libtards think there’s a thing called fully semi-automatic
The scariest thing in the whole world, the ability for ghost guns to fire 30 magazine clips in under a second. Used by the XR-15 Shorty to kill hundreds of people in seconds.
MSM reporter: The shooter used an AR15 fully semi-automatic ghost gun with a red dot laser sight sniper scope that can fire 30 magazine clips in under a second.
by F-15E Strike Eagle June 25, 2022