Chief Constable vs United Kingdom of Great Britain and Northern Ireland

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

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

Chief Constable (noun)	United Kingdom of Great Britain and Northern Ireland (noun)
the head of the police force in a county (or similar area)	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