"state or quality of being backward" in any sense, 1580s, from backward + -ness.
Entries linking to backwardness
backward adv.
"with the face to the rear, in the direction behind," c. 1300, from abakward, from Old English on bæc (see back (adv.), and compare aback) + -weard adjectival and adverbial suffix (see -ward). As an adverb, Old English had bæcling.
As an adjective, from 1550s. The meaning "behindhand with regard to progress" is attested from 1690s. To ring bells backward (from lowest to highest), c. 1500, was a signal of alarm for fire or invasion, or to express dismay. Another Middle English word for "backward, wrongly" was arseward (c. 1400); Old English had earsling.
-ness
word-forming element denoting action, quality, or state, attached to an adjective or past participle to form an abstract noun, from Old English -nes(s), from Proto-Germanic *in-assu- (cognates: Old Saxon -nissi, Middle Dutch -nisse, Dutch -nis, Old High German -nissa, German -nis, Gothic -inassus), from *-in-, originally belonging to the noun stem, + *-assu-, abstract noun suffix, probably from the same root as Latin -tudo (see -tude).