Английский Этимологический словарь - smug

- 1551, "trim, neat, spruce, smart," possibly an alteration of Low Ger. smuk "trim, neat," from M.L.G. smьcken "to adorn," and smiegen "press close." The meaning "have a self-satisfied air" is from 1701, an extension of the sense of "smooth, sleek" (1582).