monkey in the middle

Từ điển Oxford Advanced Learner 8th

ˌmonkey in the ˈmiddle 7 [monkey in the middle] BrE NAmE (NAmE) (BrE ˌpiggy in the ˈmiddle, ˌpig in the ˈmiddle) noun
1. a children's game where two people throw a ball to each other over the head of another person who tries to catch it
2. a person who is caught between two people or groups who are fighting or arguing
See also: ↑pig in the middle ▪ ↑piggy in the middle