backbench vs Great Britain

backbench and Great Britain both are nouns.

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

backbench (noun)	Great Britain (noun)
any of the seats occupied by backbenchers in the House of Commons	an island comprising England and Scotland and Wales
	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