Source : Webster's Revised Unabridged Dictionary (1913)

Separatist \Sep`a*ra*tist\, n. [Cf. F. s['e]paratiste.]
   One who withdraws or separates himself; especially, one who
   withdraws from a church to which he has belonged; a seceder
   from an established church; a dissenter; a nonconformist; a
   schismatic; a sectary.

         Heavy fines on divines who should preach in any meeting
         of separatist .                          --Macaulay.

Source : WordNet®

separatist
     adj : having separated or advocating separation from another
           entity or policy or attitude; "a breakaway faction"
           [syn: {breakaway}, {fissiparous}]
     n : an advocate of secession or separation from a larger group
         (such as an established church or a national union) [syn:
          {separationist}]