"the character of being saucy; saucy language or conduct," 1540s, from saucy + -ness. Once (1550s) as sauceliness.
Entries linking to sauciness
saucy adj.
c. 1500, "resembling sauce" (a sense now obsolete), later, of persons, words, etc., "impertinent in speech or conduct, flippantly bold, cheeky" (1520s), from sauce (n.) + -y (2). The connecting notion is sauce in the figurative sense of "that which adds intensity, piquancy in words or actions."
Compare Skelton's have eaten sauce for "be abusive." Also compare sauce malapert "impertinence" (1520s), and sauce (n.) in its obsolete use as a vocative for "impudent person" (1530s). In Shakespeare, with overtones of "wanton, lascivious," it was "a term of serious condemnation" [OED]. Also compare salty in similar senses.
-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).