national capital vs Italian capital

national capital and Italian capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
national capital	Yes	No	No	No
Italian capital	Yes	No	No	No

national capital (noun)	Italian capital (noun)
the capital city of a nation	capital and largest city of Italy; on the Tiber; seat of the Roman Catholic Church; formerly the capital of the Roman Republic and the Roman Empire