duff someone up
phrasal verb with duff verb [ T ] Australian English informal uk/dʌf/ us/dʌf/
UK informal
连续殴打，一阵猛打
to hit someone repeatedly
Two of the robbers threatened to duff the witness up if he went to the police. 其中有两名劫匪威胁目击者说如果报警就揍他。