From Longman Dictionary of Contemporary Englishtone-deafˌtone-ˈdeaf adjective APMunable to hear the difference between different musical notes
Examples from the Corpus
tone-deaf• Henry wasn't really very musical but Ivy Hooper was tone-deaf.• Years before, at Abbotsfield, Kate had told Peter that her father was tone-deaf.• Those damn dirges are still running around my brain, like a tone-deaf rat with a megaphone is trapped inside my head. 