national capital vs Djibouti

national capital and Djibouti both are nouns.

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

national capital (noun)	Djibouti (noun)
the capital city of a nation	a country in northeastern Africa on the Somali peninsula; formerly under French control but became independent in 1997
	port city on the Gulf of Aden; the capital and largest city of Djibouti