Entry 1 sense Webster, 1913 Sweetener /swēt'-ən-ẽr/ · Sweet·en·er · IPA /swˈiːtənər/ 01 n. One who, or that which, sweetens; one who palliates; that which moderates acrimony. 1. One who, or that which, sweetens; one who palliates; that which moderates acrimony.