"The magical defence of the mind against external penetration. An obscure branch of magic, but a highly useful one."
—A basic description of Occlumency

NTS: occupied Clown. Occlumency is the act of magically closing one's mind against Legilimency. It is ancient, and has existed since medieval times. It can prevent a Legilimens from accessing one's thoughts and feelings, or influencing them. A person who practises this art is known as an Occlumens.