greengrocery vs Great Britain

greengrocery and Great Britain both are nouns.

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

greengrocery (noun)	Great Britain (noun)
a greengrocer's grocery store	an island comprising England and Scotland and Wales
groceries sold by a greengrocer	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