The Collaborative International Dictionary of English v.0.48:

Theologizer \The*ol"o*gi`zer\, n.
   One who theologizes; a theologian. [R.] --Boyle.
   [1913 Webster]

WordNet (r) 3.0 (2006):

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