submachine gun

[ suhb-muh-sheen ]
/ ˌsʌb məˈʃin /

noun

a lightweight automatic or semiautomatic gun, fired from the shoulder or hip.

Origin of submachine gun

First recorded in 1915–20; sub- + machine gun
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019