Rumanian vs European

Rumanian and European both are nouns.

Word	Noun	Adjective	Verb	Adverb
Rumanian	Yes	Yes	No	No
European	Yes	Yes	No	No

As nouns, European is a hypernym of Rumanian; that is, European is a word with a broader meaning than Rumanian:

Rumanian (noun)	European (noun)
an eastern Romance language spoken in Romania	a native or inhabitant of Europe
a native or inhabitant of Romania

Rumanian (adjective)	European (adjective)
of or relating to or characteristic of the country of Romania or its people or languages	of or relating to or characteristic of Europe or the people of Europe