uncivilized vs barbarian

uncivilized is not a noun while barbarian is a noun.

Word	Noun	Adjective	Verb	Adverb
uncivilized	No	Yes	No	No
barbarian	Yes	Yes	No	No

As adjectives, uncivilized and barbarian are synonyms defined as:

Other synonyms of uncivilized include barbaric, savage, uncivilised, wild.

uncivilized (noun)	barbarian (noun)
	a member of an uncivilized people
	a crude uncouth ill-bred person lacking culture or refinement

uncivilized (adjective)	barbarian (adjective)
without civilizing influences	without civilizing influences