national capital vs Montevideo

national capital and Montevideo both are nouns.

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

national capital (noun)	Montevideo (noun)
the capital city of a nation	the capital and largest city of Uruguay; a cosmopolitan city and one of the busiest ports in South America