developing country vs country

developing country and country both are nouns.

Word	Noun	Adjective	Verb	Adverb
developing country	Yes	No	No	No
country	Yes	No	No	No

As nouns, country is a hypernym of developing country; that is, country is a word with a broader meaning than developing country:

developing country: a country that is poor and whose citizens are mostly agricultural workers but that wants to become more advanced socially and economically
country: a politically organized body of people under a single government

Other hypernyms of developing country include body politic, commonwealth, land, nation, res publica, state.

developing country (noun)	country (noun)
a country that is poor and whose citizens are mostly agricultural workers but that wants to become more advanced socially and economically	a politically organized body of people under a single government
	the people who live in a nation or country
	the territory occupied by a nation
	an area outside of cities and towns
	a particular geographical region of indefinite boundary (usually serving some special purpose or distinguished by its people or culture or geography)