Maniac

a.	1.	Raving with madness; raging with disordered intellect; affected with mania; mad.
n.	1.	A raving lunatic; a madman.

Noun	1.	maniac - an insane person Synonyms: lunatic, madman
Adj.	1.	maniac - wildly disordered; "a maniacal frenzy" Synonyms: maniacal

aliene, batty, bedlamite, berserk, borderline case, crackbrain, cracked, crackpot, crazed, crazy, delirious, dement, demented, demoniac, deranged, energumen, enthusiast, fan, fanatic, fiend, flake, fou, frantic, freak, frenetic, frenzied, furious, idiot, kook, loon, loony, lunatic, mad, madman, meshuggenah, non compos, noncompos, nut, phrenetic, psychopath, psychotic, rabid, raging, ranting, raving lunatic, screwball, unsound, violent, weirdo, wild, zealot