Dictionary.net

a personality disorder characterized by amorality and lack of affect; capable of violent acts without guilt feelings (`psychopathic personality' was once widely used but was superseded by `sociopathic personality' to indicate the social aspects of the disorder; `antisocial personality disorder' is currently the preferred term)

A personality disorder whose essential feature is a pervasive pattern of disregard for, and violation of, the rights of others that begins in childhood or early adolescence and continues into adulthood. The individual must be at least age 18 and must have a history of some symptoms of CONDUCT DISORDER before age 15. (From DSM-IV, 1994)