submachine_gun has definitions from the fields of military,arms
1
[ noun ] (military,arms) machine gun that is a portable automatic firearm

Used in print

(Peter J. White, "Report on Laos"...)

Even if it did not , how would this little world of gentle people cope with its new reality of grenades and submachine_guns ?

(Breni James, Nights of the Kill....)

He walked up_to the lieutenant 's office , leaned wearily against the gun rack that housed four rifles and a gas_gun nobody remembered having used and a submachine_gun that was occasionally tried_out on the Academy_Range .

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