(Latin) adeptus, "One who has obtained." In esotericism, one who has reached the stage of initiation and become a master in the science of esotericism.
"...whosoever reaches the fifth Initiation of the Fire [Tiphereth] becomes an adept..." —Samael Aun Weor, Tarot and Kabbalah
"Beloved disciples, you need to develop each of the twenty-two major arcana of the Tarot within yourselves. You are imitatus, or rather, one who others have put on the path of the razor’s edge. Exert yourself to become adeptus, one who is the product of one’s own deeds, the one that conquers science by his own, the child of one’s own work." —Samael Aun Weor, Alchemy and Kabbalah in the Tarot
There are three degrees of adept:
"Adeptus exemptus means already “taken out” of karma; they do not owe karma." —Samael Aun Weor, Baptism and the Philosophical Stone