stone deaf
From Longman Dictionary of Contemporary Englishstone deafˌstone ˈdeaf adjective MHHEARcompletely unable to hearExamples from the Corpusstone deaf• It was almost impossible to tell them apart, except that Arthur was stone deaf.• The following morning she was struck with a heavy fever and by the end of the day she was stone deaf.• That was another of Eunice Snell's theories, that he was a bit weak in the head and probably stone deaf too.