The Collaborative International Dictionary of English v.0.48:

Benignancy \Be*nig"nan*cy\, n.
   Benignant quality; kindliness.
   [1913 Webster]

WordNet (r) 3.0 (2006):

benignancy
    n 1: the quality of being kind and gentle [syn: benignity,
         benignancy, graciousness] [ant: malignance,
         malignancy, malignity]