to blame someone or to make them responsible for a problem that you should deal with yourself
Usage notes: In the card game poker, the buck is an object passed to the person who wins in order to remind them that they must be the first person to give money for the prize in the next game.
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to )
Parents often try to pass the buck to teachers when children misbehave in school. Bus companies are just passing the buck by saying their drivers are responsible for delays.