The Collaborative International Dictionary of English v.0.48:

Calvinistic \Cal`vin*is"tic\, Calvinistical \Cal`vin*is"tic*al\,
   a.
   Of or pertaining to Calvin, or Calvinism; following Calvin;
   accepting or Teaching Calvinism. "Calvinistic training."
   --Lowell.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Calvinistical
    adj 1: of or relating to or characteristic of Calvinism or its
           adherents [syn: Calvinist, Calvinistic,
           Calvinistical]