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]