improver
nounOne who or that which improves.
nounOne who labors at a trade for the purpose of increasing his knowledge or skill, and who accepts the opportunity of improvement as compensation in whole or in part for services rendered.
nounA pad or cushion worn by women with the object of improving the figure or the hang of a dress; a bustle.
nounOne who, or that which, improves.
nounSomething that, or someone who,
A substance added to cause
someone devoted to the promotion of human welfare and to social reforms
nouna component that is added to something to improve it