post-free vs U.K.

post-free is not a noun while U.K. is a noun.

Word	Noun	Adjective	Verb	Adverb
post-free	No	Yes	No	Yes
U.K.	Yes	No	No	No

post-free (noun)	U.K. (noun)
	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)	U.K. (adjective)
postpaid

post-free (adverb)	U.K. (adverb)
having the postage paid by the sender