rap somebody on/over the knuckles (also rap somebody’s knuckles)CRITICIZE a) to punish or criticize someone for something, but not very severely 〔不十分严厉地〕惩罚[批评]某人 He had his knuckles rapped sharply for meddling in foreign policy. 他因干涉对外政策而受到严厉批评。
b) to punish a child by hitting them on the back of their hand 打手背体罚〔儿童〕
→ rap somebody on/over the knuckles at rap2(1)