The Collaborative International Dictionary of English v.0.48:

Wiliness \Wi"li*ness\, n.
   The quality or state of being wily; craftiness; cunning;
   guile.
   [1913 Webster]

WordNet (r) 3.0 (2006):

wiliness
    n 1: shrewdness as demonstrated by being skilled in deception
         [syn: craft, craftiness, cunning, foxiness,
         guile, slyness, wiliness]