Helsinki vs Finnish capital

Helsinki and Finnish capital both are nouns.

Word	Noun	Adjective	Verb	Adverb
Helsinki	Yes	No	No	No
Finnish capital	Yes	No	No	No

As nouns, Helsinki and Finnish capital are synonyms defined as:

Helsinki and Finnish capital: the capital and largest city of Finland; located in southern Finland; a major port and commercial and cultural center

Other synonyms of Helsinki include capital of Finland, Helsingfors.

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