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]