ROGET THESAURUS
monomaniac
Madman
N
madman, lunatic, maniac, bedlamite, candidate for Bedlam, raver, madcap, crazy, energumen, automaniac,
monomaniac, dipsomaniac, kleptomaniac, hypochondriac (low spirits), crank, Tom o'Bedlam, dreamer, rhapsodist, seer, highflier, enthusiast, fanatic, fanatico, exalte, knight errant, Don Quixote, idiot.