battlewagon vs combat ship

battlewagon and combat ship both are nouns.

Word	Noun	Adjective	Verb	Adverb
battlewagon	Yes	No	No	No
combat ship	Yes	No	No	No

As nouns, combat ship is a hypernym of battlewagon; that is, combat ship is a word with a broader meaning than battlewagon:

Other hypernyms of battlewagon include war vessel, warship.

battlewagon (noun)	combat ship (noun)
large and heavily armoured warship	a government ship that is available for waging war