European country vs Serbia and Montenegro

European country and Serbia and Montenegro both are nouns.

Word	Noun	Adjective	Verb	Adverb
European country	Yes	No	No	No
Serbia and Montenegro	Yes	No	No	No

European country (noun)	Serbia and Montenegro (noun)
any one of the countries occupying the European continent	a mountainous republic in southeastern Europe bordering on the Adriatic Sea; formed from two of the six republics that made up Yugoslavia until 1992; Serbia and Montenegro were known as the Federal Republic of Yugoslavia until 2003 when they adopted the name of the Union of Serbia and Montenegro