Is returning insult for insult and slander for slander permissible by Sharia and does it fall under the category of: "And there is for you in legal retribution [saving of] life, O you [people] of understanding"?

Responding to someone who curses and insults is a permissible retribution, provided it is not excessive or includes something forbidden like slander or calumny, and that it is not an aggression against someone other than the transgressor. Allah Almighty says: "So whoever commits aggression against you, then aggress against him in the same manner that he aggressed against you" and "The recompense of an evil is an evil like it." So if he says to him: "You dog," he responds: "Rather, he is the dog," without addition or anything more vulgar. It is not permissible for the response to be a lie, a calumny, or slander. And if the initiator curses the father of the cursed person or his tribe, it is not permissible to respond in kind, because it is cursing someone who has not wronged. And forgiveness is better.