The Collaborative International Dictionary of English v.0.48:

Feasibility \Fea"si*bil*ity\ (f[=e]`z[i^]*b[i^]l"[i^]*t[y^]) n.;
   pl. Feasibilities (f[=e]`z[i^]*b[i^]l"[i^]*tiz). [from
   Feasible]
   The quality of being feasible; practicability; also, that
   which is feasible; as, before we adopt a plan, let us
   consider its feasibility.
   [1913 Webster]

         Men often swallow falsities for truths, dubiosities for
         certainties, possibilities for feasibilities. --Sir T.
                                                  Browne.
   [1913 Webster]

WordNet (r) 3.0 (2006):

feasibility
    n 1: the quality of being doable [syn: feasibility,
         feasibleness] [ant: infeasibility, unfeasibility]

Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "feasibility":
   achievability, actability, adaptability, advantage,
   advantageousness, advisability, applicability, appropriateness,
   attainability, beneficialness, compassability, convenience,
   decency, desirability, ductility, expedience, expediency, fitness,
   fittingness, flexibility, fruitfulness, handiness, malleability,
   manageability, manageableness, maneuverability, negotiability,
   operability, opportuneness, percentage, performability, pliability,
   pliancy, politicness, practicability, practicality, profit,
   profitability, propriety, prudence, realizability, rightness,
   seasonableness, seemliness, suitability, superability,
   surmountability, timeliness, untroublesomeness, usefulness,
   viability, viableness, wieldableness, wieldiness, wisdom,
   workability, worthwhileness