talk (or tell it) to the hand used to express dismissive disregard of, or indifference to, what a person has said or is saying, or to implore a person to stop speaking. US
☞ The idea is also more fully expressed as talk (or tell it) to the hand because the face isn't listening (or doesn't understand, etc.). It is typically uttered with a hand outstretched and the palm facing the person addressed.