Source : Webster's Revised Unabridged Dictionary (1913)

Knavish \Knav"ish\, a.
   1. Like or characteristic of a knave; given to knavery;
      trickish; fraudulent; dishonest; villainous; as, a knavish
      fellow, or a knavish trick. ``Knavish politicians.''
      --Macaulay.

   2. Mischievous; roguish; waggish.

            Cupid is knavish lad, Thus to make poor females mad.
                                                  --Shak.

Source : WordNet®

knavish
     adj : marked by skill in deception; "cunning men often pass for
           wise"; "deep political machinations"; "a foxy scheme";
           "a slick evasive answer"; "sly as a fox"; "tricky Dik";
           "a wily old attorney" [syn: {crafty}, {cunning}, {dodgy},
            {foxy}, {guileful}, {slick}, {sly}, {tricksy}, {tricky},
            {wily}]