national capital vs Luxemburg

national capital and Luxemburg both are nouns.

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

national capital (noun)	Luxemburg (noun)
the capital city of a nation	a grand duchy (a constitutional monarchy) landlocked in northwestern Europe between France and Belgium and Germany; an international financial center
	the capital and largest city of Luxembourg