combat ship vs warship

combat ship and warship both are nouns.

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

As nouns, combat ship and warship are synonyms defined as:

combat ship and warship: a government ship that is available for waging war

Other synonyms of combat ship include war vessel.

combat ship (noun)	warship (noun)
a government ship that is available for waging war	a government ship that is available for waging war