building vs upstairs

building and upstairs both are nouns.

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

building (noun)	upstairs (noun)
the act of constructing something	the part of a building above the ground floor
the commercial activity involved in repairing old structures or constructing new ones
a structure that has a roof and walls and stands more or less permanently in one place
the occupants of a building

building (adjective)	upstairs (adjective)
	on or of upper floors of a building

building (adverb)	upstairs (adverb)
	on a floor above
	with respect to the mind