The Collaborative International Dictionary of English v.0.48:

Benefaction \Ben`e*fac"tion\, n. [L. benefactio, fr. benefacere
   to do good to one; bene well + facere to do. See Benefit.]
   1. The act of conferring a benefit. --Johnson.
      [1913 Webster]

   2. A benefit conferred; esp. a charitable donation.
      [1913 Webster]

   Syn: Gift; present; gratuity; boon; alms.
        [1913 Webster]

WordNet (r) 3.0 (2006):

benefaction
    n 1: a contribution of money or assistance
    2: an act intending or showing kindness and good will [syn:
       benevolence, benefaction]