abnormality vs backwardness

abnormality and backwardness both are nouns.

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

As nouns, backwardness is a hypernym of abnormality; that is, backwardness is a word with a broader meaning than abnormality:

abnormality: retardation sufficient to fall outside the normal range of intelligence
backwardness: lack of normal development of intellectual capacities

Other hypernyms of abnormality include mental retardation, retardation, slowness, subnormality.

abnormality (noun)	backwardness (noun)
behavior that breaches the rule or etiquette or custom or morality	lack of normal development of intellectual capacities
marked strangeness as a consequence of being abnormal
retardation sufficient to fall outside the normal range of intelligence
an abnormal physical condition resulting from defective genes or developmental deficiencies