assault gun vs armoured vehicle

assault gun and armoured vehicle both are nouns.

Word	Noun	Adjective	Verb	Adverb
assault gun	Yes	No	No	No
armoured vehicle	Yes	No	No	No

As nouns, armoured vehicle is a hypernym of assault gun; that is, armoured vehicle is a word with a broader meaning than assault gun:

assault gun: an armored vehicle with the chassis of a tank (but no turret) and a large gun; used as an antitank weapon and to support infantry
armoured vehicle: a vehicle that is protected by armor plate

Other hypernyms of assault gun include armored vehicle.

assault gun (noun)	armoured vehicle (noun)
an armored vehicle with the chassis of a tank (but no turret) and a large gun; used as an antitank weapon and to support infantry	a vehicle that is protected by armor plate
any of the automatic rifles or semiautomatic rifles with large magazines designed for military use