punching bag noun
plural punching bags
plural punching bags
Learner's definition of PUNCHING BAG
[count] US
: a very heavy bag that usually hangs from the ceiling and that is punched for exercise or training（用于训练的悬吊式）沙袋 —
often used figuratively to describe someone who is often criticized, hit, or defeated by another person常用作比喻，指某人常遭他人批评、攻击或挫败 — called also (British) punch bag