British vs Great Britain

British and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
British	Yes	Yes	No	No
Great Britain	Yes	No	No	No

British (noun)	Great Britain (noun)
the people of Great Britain	an island comprising England and Scotland and Wales
	a monarchy in northwestern Europe occupying most of the British Isles; divided into England and Scotland and Wales and Northern Ireland; `Great Britain' is often used loosely to refer to the United Kingdom

British (adjective)	Great Britain (adjective)
of or relating to or characteristic of Great Britain or its people or culture