roof vs building

roof and building both are nouns.

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

roof (noun)	building (noun)
a protective covering that covers or forms the top of a building	the act of constructing something
protective covering on top of a motor vehicle	the commercial activity involved in repairing old structures or constructing new ones
an upper limit on what is allowed	a structure that has a roof and walls and stands more or less permanently in one place
the inner top surface of a covered area or hollow space	the occupants of a building

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