The Collaborative International Dictionary of English v.0.48:

Deistic \De*is"tic\ (d[-e]*[i^]s"t[i^]k), Deistical
\De*is"tic*al\, a.
   Pertaining to, savoring of, or consisting in, deism; as, a
   deistic writer; a deistical book.
   [1913 Webster]

         The deistical or antichristian scheme.   --I. Watts.
   [1913 Webster]

WordNet (r) 3.0 (2006):

deistic
    adj 1: of or relating to deism [syn: deist, deistic]