Machine gun vs. machine-gun
Machine gun is a noun phrase that is defined as a weapon that fires bullets rapidly as long as the trigger is held down. When hyphenated, as machine-gun, the word becomes an adjective used to describe things that happen very quickly. Machine-gun can also be a verb, to shoot something with a machine gun. However, in practice, the common spelling is machine gun for both verb and adjective forms. Examples A policewoman was under investigation today after her machine gun went off while she was unloading …