Excessive love and thought of self; the habit of regarding one's self as the center of every interest; selfishness; -- opposed to altruism.

See Ethical egoism and Psychological egoism

acting in one's self-interest; generally referred to as selfishness. There are two forms. Ethical egoism: even though we can act in the interests of others, we should always act only in our own interests. Writer Ayn Rand promoted ethical egoism. Psychological egoism: that we cannot act in the interests of others, and anything that appears to be such is actually a selfish act, because we expect to personally benefit from it.

A moral theory that commonly states that each person ought to act in his or her own Self-interest.

the tendency to consider only oneself and one's own interests