Throwing the book at someone is a popular idiom that means to punish a person severely. It implies that the person is being punished with the full force of the law or authority. While throwing the book at someone suggests tough punishment, the opposite of this could be soft or gentle punishment. Some antonyms for throwing the book at someone are forgivable, mercy, pardon, leniency, clemency, and kindness. These antonyms imply a compassionate or sympathetic approach towards someone who has committed an offense. Rather than throwing the book at someone, a sensible and empathetic response to an offense could yield more positive results.