Great Britain vs rugby football

Great Britain and rugby football both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
rugby football	Yes	No	No	No

Great Britain (noun)	rugby football (noun)
an island comprising England and Scotland and Wales	a form of football played with an oval ball
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