curb roof vs roof

curb roof and roof both are nouns.

Word	Noun	Adjective	Verb	Adverb
curb roof	Yes	No	No	No
roof	Yes	No	Yes	No

As nouns, roof is a hypernym of curb roof; that is, roof is a word with a broader meaning than curb roof:

curb roof (noun)	roof (noun)
a roof with two or more slopes on each side of the ridge	a protective covering that covers or forms the top of a building
	protective covering on top of a motor vehicle
	an upper limit on what is allowed
	the inner top surface of a covered area or hollow space

curb roof (verb)	roof (verb)
	provide a building with a roof; cover a building with a roof