fire ship vs weapon

fire ship and weapon both are nouns.

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

As nouns, weapon is a hypernym of fire ship; that is, weapon 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: any instrument or instrumentality used in fighting or hunting

Other hypernyms of fire ship include arm, weapon system.

fire ship (noun)	weapon (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
	a means of persuading or arguing