muffin man vs United Kingdom of Great Britain and Northern Ireland

muffin man and United Kingdom of Great Britain and Northern Ireland both are nouns.

Word	Noun	Adjective	Verb	Adverb
muffin man	Yes	No	No	No
United Kingdom of Great Britain and Northern Ireland	Yes	No	No	No

muffin man (noun)	United Kingdom of Great Britain and Northern Ireland (noun)
formerly an itinerant peddler of muffins	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