Do forgive a unrepentant person

Good and difficult question. It has been suggested that forgiving is a path to psychological healing, because holding a grudge has adverse effects on ones psychological well-being. This would be a good reason to forgive even the unrepentant, because it will help you, while not forgiving may not have the desired effect of punishing the perpetrator, but negatively affect your psychological well-being. Having said that, forgiveness, especially for the unrepentant, is a thorny ethical topic, because it may amount to tolerating evil. Being an agnostic, I have not addressed any religious aspect of forgiveness here, which may have different implications depending on ones denomination/faith.