The Collaborative International Dictionary of English v.0.48:

Witticism \Wit"ti*cism\, n. [From Witty.]
   A witty saying; a sentence or phrase which is affectedly
   witty; an attempt at wit; a conceit. --Milton.
   [1913 Webster]

         He is full of conceptions, points of epigram, and
         witticisms; all which are below the dignity of heroic
         verse.                                   --Addison.
   [1913 Webster]

WordNet (r) 3.0 (2006):

witticism
    n 1: a message whose ingenuity or verbal skill or incongruity
         has the power to evoke laughter [syn: wit, humor,
         humour, witticism, wittiness]

The Devil's Dictionary (1881-1906):

WITTICISM, n.  A sharp and clever remark, usually quoted, and seldom
noted; what the Philistine is pleased to call a "joke."