This phrase occurs several times in the book of Leviticus (Leviticus 19:12; Leviticus 20:3; Leviticus 21:6). The verb profane
(ḥll) means to make something unholy. Profaning the name of God occurs when his name is misused, or by doing something that God expressly disapproves of. Sexual immorality among the Israelites denigrates the name of God.
21 Tu ne livreras aucun de tes enfants pour le sacrifier à Moloc, et tu ne profaneras point le nom de ton Dieu. Je suis l'Eternel.