The Collaborative International Dictionary of English v.0.48:

Autarchy \Au"tar*chy\, n. [Gr. ? independence; a'yto`s self +
   'arkei^n to be sufficient.]
   1. Self-sufficiency, especially economic self-sufficiency as
      applied to nations. [Obs.] --Milton.
      [1913 Webster +PJC]

   2. same as autarky.

   Syn: autarky.
        [WordNet 1.5] autarkic

WordNet (r) 3.0 (2006):

autarchy
    n 1: economic independence as a national policy [syn: autarky,
         autarchy]
    2: a political system governed by a single individual [syn:
       autocracy, autarchy]

Moby Thesaurus II by Grady Ward, 1.0:

79 Moby Thesaurus words for "autarchy":
   Caesarism, Declaration of Independence, Stalinism,
   absolute monarchy, absolutism, aristocracy, autarky,
   authoritarianism, autocracy, autonomy, benevolent despotism,
   coalition government, colonialism, commonwealth,
   constitutional government, constitutional monarchy, czarism,
   democracy, despotism, dictatorship, dominion rule, duarchy,
   duumvirate, dyarchy, federal government, federation, feudal system,
   garrison state, gerontocracy, heteronomy, hierarchy, hierocracy,
   home rule, independence, individualism, inner-direction, kaiserism,
   limited monarchy, martial law, meritocracy, militarism,
   military government, mob rule, mobocracy, monarchy, neocolonialism,
   ochlocracy, oligarchy, one-man rule, one-party rule, pantisocracy,
   paternalism, patriarchate, patriarchy, police state,
   pure democracy, regency, representative democracy,
   representative government, republic, rugged individualism,
   self-containment, self-determination, self-direction,
   self-government, self-reliance, self-sufficiency, social democracy,
   stratocracy, technocracy, thearchy, theocracy,
   totalitarian government, totalitarian regime, totalitarianism,
   triarchy, triumvirate, tyranny, welfare state