The Collaborative International Dictionary of English v.0.48:

Dishonesty \Dis*hon"es*ty\, n. [Cf. OF. deshonest['e], F.
   d['e]shonn[^e]tet['e].]
   1. Dishonor; dishonorableness; shame. [Obs.] "The hidden
      things of dishonesty." --2 Cor. iv. 2.
      [1913 Webster]

   2. Want of honesty, probity, or integrity in principle; want
      of fairness and straightforwardness; a disposition to
      defraud, deceive, or betray; faithlessness.
      [1913 Webster]

   3. Violation of trust or of justice; fraud; any deviation
      from probity; a dishonest act.
      [1913 Webster]

   4. Lewdness; unchastity. --Shak.
      [1913 Webster]

WordNet (r) 3.0 (2006):

dishonesty
    n 1: the quality of being dishonest [ant: honestness,
         honesty]
    2: lack of honesty; acts of lying or cheating or stealing [syn:
       dishonesty, knavery]