The Collaborative International Dictionary of English v.0.48:

Disinterested \Dis*in"ter*est*ed\, a. [Cf. Disinteressed.]
   Not influenced by regard to personal interest or advantage;
   free from selfish motive; having no relation of interest or
   feeling; not biased or prejudiced; as, a disinterested
   decision or judge.
   [1913 Webster]

         The happiness of disinterested sacrifices. --Channing.

   Syn: Unbiased; impartial; uninterested; indifferent.
        [1913 Webster]

WordNet (r) 3.0 (2006):

disinterested
    adj 1: unaffected by self-interest