The Collaborative International Dictionary of English v.0.48:

autarchic \autarchic\, autarchical \autarchical\adj.
   1. 1 of or pertaining to autocracy.

   Syn: autarchical
        [WordNet 1.5]

WordNet (r) 3.0 (2006):

autarchic
    adj 1: of or relating to or characterized by autarchy [syn:
           autarchic, autarchical, autarkical]

Moby Thesaurus II by Grady Ward, 1.0:

19 Moby Thesaurus words for "autarchic":
   arbitrary, autarkic, autocratic, autonomous, commanding, despotic,
   dogmatic, imperious, independent, monocratic, nonconstitutional,
   self-dependent, self-reliant, self-sufficient, separate, sovereign,
   tyrannical, tyrannous, undemocratic