Source : Webster's Revised Unabridged Dictionary (1913)

Theistic \The*is"tic\, Theistical \The*is"tic*al\, a.
   Of or pertaining to theism, or a theist; according to the
   doctrine of theists.

Source : WordNet®

theistical
     adj : of or relating to theism [syn: {theist}, {theistic}]