The Collaborative International Dictionary of English v.0.48:

Self-interest \Self`-in"ter*est\, n.
   Private interest; the interest or advantage of one's self.
   [1913 Webster]

WordNet (r) 3.0 (2006):

self-interest
    n 1: taking advantage of opportunities without regard for the
         consequences for others [syn: opportunism, self-
         interest, self-seeking, expedience]
    2: concern for your own interests and welfare [syn: egoism,
       egocentrism, self-interest, self-concern, self-
       centeredness] [ant: altruism, selflessness]

Moby Thesaurus II by Grady Ward, 1.0:

43 Moby Thesaurus words for "self-interest":
   acquisitiveness, autism, careerism, ego, ego trip, egocentricity,
   egocentrism, egoism, egoisticalness, egotism, egotisticalness,
   graspingness, greed, individualism, interest, narcissism,
   personal aims, personal ambition, personal desires, personalism,
   possessiveness, privatism, remoteness, self-absorption,
   self-admiration, self-advancement, self-centeredness,
   self-centerment, self-consideration, self-containment,
   self-devotion, self-esteem, self-indulgence, self-interestedness,
   self-jealousy, self-occupation, self-pleasing, self-seeking,
   self-serving, self-solicitude, self-sufficiency, selfishness,
   selfism