UK vs redbrick

UK is a noun but redbrick is not a noun.

Word	Noun	Adjective	Verb	Adverb
UK	Yes	No	No	No
redbrick	No	Yes	No	No

UK (noun)	redbrick (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

UK (adjective)	redbrick (adjective)
	of or relating to British universities founded in the late 19th century or the 20th century