fire ship vs weapon system

fire ship and weapon system both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire ship	Yes	No	No	No
weapon system	Yes	No	No	No

As nouns, weapon system is a hypernym of fire ship; that is, weapon system is a word with a broader meaning than fire ship:

fire ship: a weapon consisting of a ship carrying explosives that is set adrift to destroy enemy ships
weapon system: any instrument or instrumentality used in fighting or hunting

Other hypernyms of fire ship include arm, weapon.

fire ship (noun)	weapon system (noun)
a weapon consisting of a ship carrying explosives that is set adrift to destroy enemy ships	any instrument or instrumentality used in fighting or hunting