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