Narcissism is a term with a wide range of meanings, depending on whether it is used to describe a central concept of psychoanalytic theory, a mental illness, a social or cultural problem, or simply a personality trait. Except in the sense of primary narcissism or healthy self-love, "narcissism" usually is used to describe some kind of problem in a person or group's relationships with self and others. In everyday speech, "narcissism" often means egoism, vanity, conceit, or simple selfishness. Applied to a social group, it is sometimes used to denote elitism or an indifference to the plight of others. In psychology, the term is used to describe both normal self-love and unhealthy self-absorption due to a disturbance in the sense of self.

The word narcissism comes from the Greek myth of Narcissus. Narcissus was a handsome Greek youth who rejected the desperate advances of the nymph Echo. As punishment, he was doomed to fall in love with his own reflection in a pool of water. Unable to consummate his love, Narcissus "lay gazing enraptured into the pool, hour after hour", and finally changed into a flower that bears his name, the narcissus.