monomaniac UK /ˌmɒnəʊˈmeɪnɪæk/US /ˌmɑnoʊˈmeɪnɪæk/adjective 1noun 1forms 1 adjective1 •Focused on one thing above all others. noun1 •A person who is obsessed with a single thing, to the exclusion of other concerns.Harry knew now that the old man was crazy, or at least a monomaniac, and, though he seemed harmless enough, it was of course possible that he might be dangerous. — 1873 formsmonomaniacs
