The Collaborative International Dictionary of English v.0.48:

Absolutist \Ab"so*lu`tist\, n.
   1. One who is in favor of an absolute or autocratic
      government.
      [1913 Webster]

   2. (Metaph.) One who believes that it is possible to realize
      a cognition or concept of the absolute. --Sir. W.
      Hamilton.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Absolutist \Ab"so*lu`tist\, a.
   Of or pertaining to absolutism; arbitrary; despotic; as,
   absolutist principles.
   [1913 Webster]

WordNet (r) 3.0 (2006):

absolutist
    adj 1: pertaining to the principle of totalitarianism [syn:
           absolutist, absolutistic]
    n 1: one who advocates absolutism