Psychopath

noun

1. A person with a personality disorder indicated by a pattern of lying, cunning, manipulating, glibness, exploiting, heedlessness, arrogance, delusions of grandeur, sexual promiscuity, low self-control, disregard for morality, lack of acceptance of responsibility, callousness, and lack of empathy and remorse. Such an individual may be especially prone to violent and criminal offenses.
2. A person with no moral conscience who perpetrates especially gruesome or bizarre violent acts.
3. A person diagnosed with antisocial or dissocial personality disorder.
4. A person diagnosed with any mental disorder.