The Collaborative International Dictionary of English v.0.48:

Unconverted \Un`con*vert"ed\, a.
   1. Not converted or exchanged.
      [1913 Webster]

   2. Not changed in opinion, or from one faith to another.
      Specifically:
      [1913 Webster]
      (a) Not persuaded of the truth of the Christian religion;
          heathenish. --Hooker.
          [1913 Webster]
      (b) Unregenerate; sinful; impenitent. --Baxter.
          [1913 Webster]

WordNet (r) 3.0 (2006):

unconverted
    adj 1: not converted [syn: unconverted, unpersuaded]