rag week vs UK

rag week and UK both are nouns.

Word	Noun	Adjective	Verb	Adverb
rag week	Yes	No	No	No
UK	Yes	No	No	No

rag week (noun)	UK (noun)
a week at British universities during which side-shows and processions of floats are organized to raise money for charities	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