pub vs Great Britain

pub and Great Britain both are nouns.

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

pub (noun)	Great Britain (noun)
tavern consisting of a building with a bar and public rooms; often provides light meals	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