Great Britain vs sweet Fanny Adams

Great Britain and sweet Fanny Adams both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
sweet Fanny Adams	Yes	No	No	No

Great Britain (noun)	sweet Fanny Adams (noun)
an island comprising England and Scotland and Wales	little or nothing at all
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