country vs buffer state

country and buffer state both are nouns.

Word	Noun	Adjective	Verb	Adverb
country	Yes	No	No	No
buffer state	Yes	No	No	No

As nouns, buffer state is a hyponym of country; that is, buffer state is a word with a more specific, narrower meaning than country:

country (noun)	buffer state (noun)
a politically organized body of people under a single government	a small neutral state between two rival powers
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)