Helsingfors vs national capital

Helsingfors and national capital both are nouns.

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

Helsingfors (noun)	national capital (noun)
the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center	the capital city of a nation