kangaroo court
noun [ C ] uk/ˌkæŋ.ɡər.uː ˈkɔːt/ us/ˌkæŋ.ɡə.ruː ˈkɔːrt/
袋鼠法庭（指在监狱、工会或其他组织中私设的公堂或非正规的法庭）
an unofficial court set up by a group of people, especially in a prison, trade union, or other organization, to deal with a disagreement or with a member of the group who is considered to have broken the rules