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]

WordNet (r) 3.0 (2006):

psychopathy
    n 1: any disease of the mind; the psychological state of someone
         who has emotional or behavioral problems serious enough to
         require psychiatric intervention [syn: mental illness,
         mental disease, psychopathy] [ant: mental health]