Great Britain vs shadow cabinet

Great Britain and shadow cabinet both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
shadow cabinet	Yes	No	No	No

Great Britain (noun)	shadow cabinet (noun)
an island comprising England and Scotland and Wales	a group of senior members of the political party that is out of power; these members would probably assume corresponding positions as ministers in the British Cabinet if their party was elected
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