Welcome to English in a Minute from home! A tone is a sound you hear in music or in someone's voice. And deaf means unable to hear. So, what could "tone deaf" mean as an idiom? Speaker A: Ugh. Jonathan, Cynthia is so tone deaf. She went to Duncan's party with peanut butter cookies and a big bag of peanuts.Speaker B: What?! Duncan is allergic to nuts. His party invitation … [Read more...] about Tone Deaf (Idioms)