Give someone the back of one’s hand = Reject or feel contempt
拒絕, 駁回, 否決, 輕蔑, 鄙視
You have given those who sought to assure that the persons responsible would be held accountable the back of your hand.
Unimpressed with him, she gave the back of her hand to his suggestion. This phrase is usually the object of a verb such as give or show. [Second half of 1700s]
Back of the hand similarly means “an insult” in the term back-handed compliment (see under left-handed compliment).