Great Britain vs constable

Great Britain and constable both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
constable	Yes	No	No	No

Great Britain (noun)	constable (noun)
an island comprising England and Scotland and Wales	a lawman with less authority and jurisdiction than a sheriff
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	a police officer of the lowest rank