wickedness (n.)

c. 1200, extended form of earlier wick "bad, wicked, false" (12c.), which apparently is an adjectival use of Old English wicca "wizard" (see witch). Formed as if a past participle, but there is no corresponding verb. For evolution, compare wretched from wretch. Slang ironic sense of "wonderful" first attested 1920, in F. Scott Fitzgerald. As an adverb from early 15c. Related: Wickedly.

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).