punching bag
US /ˈpʌn.tʃɪŋ ˌbæɡ/
UK /ˈpʌn.tʃɪŋ ˌbæɡ/

1.
沙袋, 拳击袋
a heavy bag, usually made of leather or canvas, filled with sand or other material, that is suspended from above and used for punching practice by boxers or other martial artists
:
•
He trains daily with a punching bag to improve his boxing skills.
他每天用沙袋训练以提高拳击技能。
•
The gym has several different types of punching bags.
健身房有几种不同类型的沙袋。
2.
出气筒, 替罪羊, 受批评的对象
a person or thing that is repeatedly subjected to criticism, abuse, or attack
:
•
He became the team's punching bag after a series of losses.
在一系列失败后,他成了球队的出气筒。
•
The manager used the new intern as a punching bag for all his frustrations.
经理把新来的实习生当作出气筒,发泄所有的不满。