Толковый словарь английского языка Oxford English Reference - maniac

comb. form forming adjectives and nouns meaning 'affected with -mania' or 'a person affected with -mania' (nymphomaniac). MANIAC n. & adj. --n. 1 colloq. a person exhibiting extreme symptoms of wild behaviour etc.; a madman. 2 colloq. an obsessive enthusiast. 3 Psychol. archaic a person suffering from mania. --adj. of or behaving like a maniac. Derivatives maniacal adj. maniacally adv. Etymology: LL maniacus f. late Gk maniakos (as MANIA)