Danish vs Scandinavian

Danish and Scandinavian both are nouns.

Word	Noun	Adjective	Verb	Adverb
Danish	Yes	Yes	No	No
Scandinavian	Yes	Yes	No	No

As nouns, Scandinavian is a hypernym of Danish; that is, Scandinavian is a word with a broader meaning than Danish:

Danish: a Scandinavian language that is the official language of Denmark
Scandinavian: the northern family of Germanic languages that are spoken in Scandinavia and Iceland

Other hypernyms of Danish include Nordic, Norse, North Germanic, North Germanic language, Scandinavian language.

Danish (noun)	Scandinavian (noun)
a Scandinavian language that is the official language of Denmark	the northern family of Germanic languages that are spoken in Scandinavia and Iceland
	an inhabitant of Scandinavia

Danish (adjective)	Scandinavian (adjective)
of or relating to or characteristic of Denmark or the Danes or their language	of or relating to Scandinavia or its peoples or cultures