Great Britain vs crossbencher

Great Britain and crossbencher both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
crossbencher	Yes	No	No	No

Great Britain (noun)	crossbencher (noun)
an island comprising England and Scotland and Wales	a member of the House of Commons who does not vote regularly with either the government or the Opposition
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