Source : Webster's Revised Unabridged Dictionary (1913)

Maniac \Ma"ni*ac\, a. [F. maniaque. See {Mania}.]
   Raving with madness; raging with disordered intellect;
   affected with mania; mad.

Maniac \Ma"ni*ac\, n.
   A raving lunatic; a madman.

Source : WordNet®

maniac
     adj : wildly disordered; "a maniacal frenzy" [syn: {maniacal}, {maniac(p)}]

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