Great Britain vs pull-up

Great Britain and pull-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
pull-up	Yes	No	No	No

Great Britain (noun)	pull-up (noun)
an island comprising England and Scotland and Wales	an arm exercise performed by pulling yourself up on a horizontal bar until your chin is level with the bar
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	a roadside cafe especially for lorry drivers