Selfishness is a synonym of egoism.
As nouns the difference between selfishness and egoism
is that selfishness
is the quality of being selfish, the condition of putting one's own interests before those of others while egoism
is the tendency to think of self and self-interest.
Other Comparisons: What's the difference?
the quality of being selfish, the condition of putting one's own interests before those of others
The tendency to think selfishly with exclusive self-interest in mind.
(ethics) The belief that moral behavior should be directed toward one's self-interest only.
(nonstandard, by confusion of the similar words) egotism
* (tendency to think of self) selfishness
* (tendency to think of self) altruism
* misanthropy (hatred of human race)