war vs civil war

war and civil war both are nouns.

Word	Noun	Adjective	Verb	Adverb
war	Yes	No	Yes	No
civil war	Yes	No	No	No

As nouns, civil war is a hyponym of war; that is, civil war is a word with a more specific, narrower meaning than war:

war (noun)	civil war (noun)
the waging of armed conflict against an enemy	a war between factions in the same country
a concerted campaign to end something that is injurious
an active struggle between competing entities
a legal state created by a declaration of war and ended by official declaration during which the international rules of war apply

war (verb)	civil war (verb)
make or wage war