psy·cho·path 
Pronunciation: 'sI-k&-"path
Function: noun
Etymology: International Scientific Vocabulary
: a mentally ill or unstable person; especially : a person having a psychopathic personality
1psy·cho·path·ic
Pronunciation: "sI-k&-'pa-thik
Function: adjective
: of, relating to, or characterized by psychopathy
psy·chop·a·thy
Pronunciation: sI-'kä-p&-thE
Function: noun
Etymology: International Scientific Vocabulary
: mental disorder; especially : extreme mental disorder marked usually by egocentric and antisocial activity
so·cio·path
Pronunciation: 'sO-sE-&-"path, 'sO-sh(E-)&-
Function: noun
: PSYCHOPATH