IR vs United Kingdom of Great Britain and Northern Ireland

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

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

IR (noun)	United Kingdom of Great Britain and Northern Ireland (noun)
a board of the British government that administers and collects major direct taxes	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