backwardness vs backward

backwardness is a noun but backward is not a noun.

Word	Noun	Adjective	Verb	Adverb
backwardness	Yes	No	No	No
backward	No	Yes	No	Yes

backwardness (noun)	backward (noun)
lack of normal development of intellectual capacities

backwardness (adjective)	backward (adjective)
	directed or facing toward the back or rear
	(used of temperament or behavior) marked by a retiring nature
	retarded in intellectual development
	having made less than normal progress

backwardness (adverb)	backward (adverb)
	in a manner or order or direction the reverse of normal
	in or to or toward a past time
	at or to or toward the back or rear