first-class honours degree vs Great Britain

first-class honours degree and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
first-class honours degree	Yes	No	No	No
Great Britain	Yes	No	No	No

first-class honours degree (noun)	Great Britain (noun)
an honours degree of the highest class	an island comprising England and Scotland and Wales
	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