Whether derision can be a mortal sin?

❌ Objection 1 : It would seem that derision cannot be a mortal sin. Every mortal sin is contrary to charity. But derision does not seem contrary to charity, for sometimes it takes place in jest among friends, wherefore it is known as "making fun." Therefore derision cannot be a mortal sin.

❌ Objection 2 : Further, the greatest derision would appear to be that which is done as an injury to God. But derision is not always a mortal sin when it tends to the injury of God: else it would be a mortal sin to relapse into a venial sin of which one has repented. For Isidore says (De Sum. Bon. ii, 16) that "he who continues to do what he has repented of, is a derider and not a penitent." It would likewise follow that all hypocrisy is a mortal sin, because, according to Gregory (Moral. xxxi, 15) "the ostrich signifies the hypocrite, who derides the horse, i.e. the just man, and his rider, i.e. God." Therefore derision is not a mortal sin.

❌ Objection 3 : Further, reviling and backbiting seem to be graver sins than derision, because it is more to do a thing seriously than in jest. But not all backbiting or reviling is a mortal sin. Much less therefore is derision a mortal sin.