(of an action or thing) done or operating in an impressively smooth, efficient, and apparently effortless way. (of skin or hair) smooth and glossy. An oil slick. A race car or bicycle tire without a tread, for use in dry weather conditions. A glossy magazine. Make (one's hair) flat, smooth, and glossy by applying water, oil, or cream to it. Make someone or something smart, tidy, or stylish.