Tommy's Gun is a term used to describe a type of submachine gun developed by the British during World War II. The gun was designed to be lightweight and easy to use, and was given the name 'Tommy's Gun' after the nickname for British soldiers, 'Tommies'. The crossword solution for Tommy's Gun is STEN, which is an acronym for the names of the two designers, Reginald V. Shepherd and Harold Turpin.