Great Britain vs kerb crawler

Great Britain and kerb crawler both are nouns.

Word	Noun	Adjective	Verb	Adverb
Great Britain	Yes	No	No	No
kerb crawler	Yes	No	No	No

Great Britain (noun)	kerb crawler (noun)
an island comprising England and Scotland and Wales	someone who drives slowly along the curb seeking sex from prostitutes or other women
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