The Collaborative International Dictionary of English v.0.48:
Wittiness \Wit"ti*ness\, n. The quality of being witty. [1913 Webster]WordNet (r) 3.0 (2006):
wittiness n 1: a message whose ingenuity or verbal skill or incongruity has the power to evoke laughter [syn: wit, humor, humour, witticism, wittiness]