punch·bag
noun/ˈpʌntʃbæɡ/
/ˈpʌntʃbæɡ/
(British English) (North American English punching bag)
- a heavy leather bag, hung on a rope, which is hit with the fists (= closed hands), especially by boxers as part of training, or as a form of exercise
沙袋（悬吊式，用于拳击训练）