Source : Webster's Revised Unabridged Dictionary (1913)

Madman \Mad"man\, n.; pl. {Madmen}.
   A man who is mad; lunatic; a crazy person.

         When a man mistakes his thoughts for person and things,
         he is mad. A madman is properly so defined.
                                                  --Coleridge.

Source : WordNet®

madman
     n : an insane person [syn: {lunatic}, {maniac}]