punching_bag
1. [ noun ] a person on whom another person vents their anger
Examples:

"he resigned because his boss used him as a punching bag"

Related terms: victim
2. [ noun ] (boxing,games) an inflated ball or bag that is suspended and punched for training in boxing
Synonyms: punchball punch_bag punching_ball
Related terms: ball
Similar spelling:   punching_ball
  punishing