im·prov·er \ə̇mˈprüvə(r)\noun : one that improves: as a.chiefly Britain (1): an employee who accepts instruction or the opportunity to work in place of wages (2): a worker who has completed an apprenticeship but is not yet qualified as a full-fledged member of a trade or occupation b.: a device for giving shape to a dress; especially: bustle c.: an agent added to improve a substance < potassium bromate is used as a flour improver >