Is it permissible to insult or curse someone who is not present as a joke, knowing that the other party is aware of that and no objection results from it?

Allah praised the believers for their aversion to idle talk (laghw), which includes falsehood, polytheism, sins, and any useless words or actions. A believer should accustom their tongue to good speech and avoid obscene and vulgar language. One should turn away from words that bring no benefit, for cursing is an ugly word, and a Muslim should keep their tongue pure from it. The tongue should be occupied with what benefits one, so one should either speak good or remain silent. Scholars have admonished against cursing animals because it may lead to accustoming the tongue to disreputable speech.