The Collaborative International Dictionary of English v.0.48:

Selfishness \Self"ish*ness\, n.
   The quality or state of being selfish; exclusive regard to
   one's own interest or happiness; that supreme self-love or
   self-preference which leads a person to direct his purposes
   to the advancement of his own interest, power, or happiness,
   without regarding those of others.
   [1913 Webster]

         Selfishness, -- a vice utterly at variance with the
         happiness of him who harbors it, and, as such,
         condemned by self-love.                  --Sir J.
                                                  Mackintosh.
   [1913 Webster]

   Syn: See Self-love.
        [1913 Webster]

WordNet (r) 3.0 (2006):

selfishness
    n 1: stinginess resulting from a concern for your own welfare
         and a disregard of others [ant: unselfishness]

Moby Thesaurus II by Grady Ward, 1.0:

20 Moby Thesaurus words for "selfishness":
   autotheism, ego, egocentricity, egocentrism, egoism,
   egoisticalness, egotism, egotisticalness, individualism, self,
   self-absorption, self-centeredness, self-centerment, self-interest,
   self-regard, self-seeking, self-worship, selfhood, selfism,
   selfness