pony-trekking vs Great Britain

pony-trekking and Great Britain both are nouns.

Word	Noun	Adjective	Verb	Adverb
pony-trekking	Yes	No	No	No
Great Britain	Yes	No	No	No

pony-trekking (noun)	Great Britain (noun)
a sport in which people ride across country on ponies	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