Hypocrisy (hiding hatred behind kind words) and slander are both forms of dishonesty about others. Both characterise the fool.
Memory phrase: Honesty and kindness — not fake friendship.
Talk about it: Have you ever had a friend who was kind to your face but said unkind things behind your back? How did it feel?
Prayer: God, keep me from pretending to be kind while hiding bad feelings. Help me be honest and truly loving.