Great Britain vs new town

Great Britain and new town both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
new town	Yes	No	No	No

Great Britain (noun)	new town (noun)
an island comprising England and Scotland and Wales	a planned urban community created in a rural or undeveloped area and designed to be self-sufficient with its own housing and education and commerce and recreation
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