Italian capital vs national capital

Italian capital and national capital both are nouns.

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

Italian capital (noun)	national capital (noun)
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	the capital city of a nation