What is the origin of mystique?

Mystique “a framework of ideas endowing a person with profound meaning” is a borrowing from French and is cognate to English mystic. Both mystic and mystique derive by way of Latin from Ancient Greek mýstēs “initiate into the mysteries”; mysteries, in this context, are sacred rites and customs only known to a small, select group of people—much like how only one person or a few people know the facts behind a mystery. Mýstēs comes from the verb myeîn “to initiate, teach,” from the similarly spelled verb mýein “to close (the lips or eyes).” The implication here is that, when new initiates are exposed to the mysteries, they will stay close-lipped about what they see. Mystique was first recorded in English in the early 1890s.