DUMB

(SILENT) [adjective] [not gradable] - permanently or temporarily unable to speakHe's been deaf and dumb since birth.She was struck dumb by what she had seen.Although she doesn't get on very well with people, she's very kind to dumb animals (= animals).(UK informal) Unable to speak Chinese, I had to describe what I needed using dumb show (= hand actions and movements but not speech).A dumb waiter is a small lift (= device used to move things from one level of a building to another) used esp. in restaurants to deliver food from the kitchen.