The Collaborative International Dictionary of English v.0.48:

Theologist \The*ol"o*gist\, n.
   A theologian.
   [1913 Webster]

WordNet (r) 3.0 (2006):

theologist
    n 1: someone who is learned in theology or who speculates about
         theology [syn: theologian, theologist, theologizer,
         theologiser]