post-free vs Great Britain

post-free is not a noun while Great Britain is a noun.

Word	Noun	Adjective	Verb	Adverb
post-free	No	Yes	No	Yes
Great Britain	Yes	No	No	No

post-free (noun)	Great Britain (noun)
	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

post-free (adjective)	Great Britain (adjective)
postpaid

post-free (adverb)	Great Britain (adverb)
having the postage paid by the sender