1. (v. t.) To change or modify in any way for the better

2. (v. t.) by simply removing what is erroneous, corrupt, superfluous, faulty, and the like;

3. (v. t.) by supplying deficiencies;

4. (v. t.) by substituting something else in the place of what is removed; to rectify.

5. (v. i.) To grow better by rectifying something wrong in manners or morals; to improve.