barbarian vs uncivilized

barbarian is a noun but uncivilized is not a noun.

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

As adjectives, barbarian and uncivilized are synonyms defined as:

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

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

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