The Collaborative International Dictionary of English v.0.48:

Self-sufficient \Self`-suf*fi"cient\, a.
   1. Sufficient for one's self without external aid or
      cooperation.
      [1913 Webster]

            Neglect of friends can never be proved rational till
            we prove the person using it omnipotent and
            self-sufficient, and such as can never need any
            mortal assistance.                    --South.
      [1913 Webster]

   2. Having an overweening confidence in one's own abilities or
      worth; hence, haughty; overbearing. "A rash and
      self-sufficient manner." --I. Watts.
      [1913 Webster]

WordNet (r) 3.0 (2006):

self-sufficient
    adj 1: able to provide for your own needs without help from
           others; "a self-sufficing economic unit" [syn: self-
           sufficient, self-sufficing, self-sustaining]

Moby Thesaurus II by Grady Ward, 1.0:

116 Moby Thesaurus words for "self-sufficient":
   acquisitive, ambitious for self, autarchic, autarkic, autistic,
   autonomous, bashful, careerist, close, closed, complacent,
   consequential, dissociable, egotistical, erect, free-spirited,
   freewheeling, grasping, greedy, house-proud, incompatible,
   independent, individual, individualistic, inner-directed,
   insociable, mopey, mopish, morose, narcissan, narcissine,
   narcissistic, narcistic, neutral, nonaligned, nongregarious,
   nonpartisan, one-man, overproud, overweening, personalistic,
   possessive, prideful, privatistic, proud, proud as Lucifer,
   proud-blooded, proud-looking, proud-minded, proud-spirited,
   proudful, proudhearted, purse-proud, remote, self-absorbed,
   self-admiring, self-advancing, self-approving, self-assuming,
   self-besot, self-centered, self-complacent, self-confident,
   self-congratulating, self-congratulatory, self-considerative,
   self-contained, self-content, self-contented, self-delighting,
   self-dependent, self-determined, self-devoted, self-directing,
   self-endeared, self-esteeming, self-governed, self-governing,
   self-gratulating, self-gratulatory, self-important, self-indulgent,
   self-interested, self-jealous, self-loving, self-occupied,
   self-pleasing, self-reliant, self-respecting, self-satisfied,
   self-seeking, self-serving, self-subsistent, self-supporting,
   self-sustained, self-sustaining, selfish, smug, snug,
   socially incompatible, sovereign, stiff-necked, sullen,
   third-force, third-world, unclubbable, uncommunicative,
   uncompanionable, uncongenial, unfriendly, ungenial, unit,
   unsociable, unsocial, vain, vainglorious