cha·toy·ant I. \shəˈtȯiənt, |sha.ˌtwä|yäⁿ\adjective Etymology: French, from present participle of chatoyer to shine like a cat's eyes, from chat cat, from Late Latin cattus — more at cat : having a changeable luster or color especially marked by an undulating narrow band of white light < a dress of chatoyant silk > < a cat's eye chatoyant in the dark > < an unusual chatoyant aquamarine — Journal of Gemmology > II. noun (-s) : a chatoyant gem