punching bag

Noun punching bag has 2 senses

• punching bag(n = noun.person) - a person on whom another person vents their anger; "he resigned because his boss used him as a punching bag"
is a kind of victim

• punching bag(n = noun.artifact) punch bag, punchball, punching ball - an inflated ball or bag that is suspended and punched for training in boxing;
is a kind of ball