United Kingdom of Great Britain and Northern Ireland vs starkers

United Kingdom of Great Britain and Northern Ireland is a noun but starkers is not a noun.

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

United Kingdom of Great Britain and Northern Ireland (noun)	starkers (noun)
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

United Kingdom of Great Britain and Northern Ireland (adjective)	starkers (adjective)
	(British informal) stark naked