Britain vs invigilator

Britain and invigilator both are nouns.

Word	Noun	Adjective	Verb	Adverb
Britain	Yes	No	No	No
invigilator	Yes	No	No	No

Britain (noun)	invigilator (noun)
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	someone who watches examination candidates to prevent cheating