The Collaborative International Dictionary of English v.0.48:

Tractability \Tract`a*bil"i*ty\, n. [L. tractabilitas: cf.F.
   tractabilite.]
   The quality or state of being tractable or docile; docility;
   tractableness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

tractability
    n 1: the trait of being easily persuaded [syn: tractability,
         tractableness, flexibility] [ant: intractability,
         intractableness]