The Collaborative International Dictionary of English v.0.48:

Self-government \Self`-gov"ern*ment\, n.
   1. The act of governing one's self, or the state of being
      governed by one's self; self-control; self-command.
      [1913 Webster]

   2. Hence, government of a community, state, or nation by the
      joint action of the mass of people constituting such a
      civil body; also, the state of being so governed;
      democratic government; democracy.
      [1913 Webster]

            It is to self-government, the great principle of
            popular representation and administration, -- the
            system that lets in all to participate in the
            councels that are to assign the good or evil to all,
            -- that we may owe what we are and what we hope to
            be.                                   --D. Webster.
      [1913 Webster]

WordNet (r) 3.0 (2006):

self-government
    n 1: government of a political unit by its own people [syn:
         self-government, self-determination, self-rule]

Moby Thesaurus II by Grady Ward, 1.0:

102 Moby Thesaurus words for "self-government":
   Declaration of Independence, absolute monarchy, aplomb,
   aristocracy, autarchy, autarky, autocracy, automatic control,
   automation, automatism, automatization, autonomy,
   coalition government, colonialism, commonwealth, composure,
   constitutional government, constitutional monarchy, constraint,
   control, democracy, dictatorship, discipline, dominion rule,
   duarchy, duumvirate, dyarchy, federal government, federation,
   feudal system, freedom, garrison state, gerontocracy, heteronomy,
   hierarchy, hierocracy, home rule, independence, individualism,
   inner-direction, internationalism, internationality,
   limited monarchy, martial law, meritocracy, militarism,
   military government, mob rule, mobocracy, monarchy, nationalism,
   nationality, nationhood, neocolonialism, ochlocracy, oligarchy,
   pantisocracy, patriarchate, patriarchy, peoplehood, police state,
   possession, pure democracy, regency, representative democracy,
   representative government, republic, restraint,
   rugged individualism, self-action, self-activity, self-command,
   self-conquest, self-containment, self-control, self-denial,
   self-determination, self-direction, self-discipline, self-mastery,
   self-motion, self-possession, self-propulsion, self-regulation,
   self-reliance, self-restraint, self-sufficiency, social democracy,
   sovereign nationhood, sovereignty, statehood, stratocracy,
   technocracy, thearchy, theocracy, totalitarian government,
   totalitarian regime, triarchy, triumvirate, tyranny, welfare state,
   willpower