psychopathist

from The Collaborative International Dictionary of English v.0.48

Psychopathy \Psy*chop"a*thy\, n. [Psycho- + Gr. ?, ?.] (Med.)
   Mental disease. See {Psychosis}, 2. -- {Psy`cho*path"ic}, a.
   -- {Psy*chop"a*thist}, n.
   [1913 Webster]