improve

American Heritage® Dictionary of the English Language, Fourth Edition

1. v. To raise to a more desirable or more excellent quality or condition; make better.
2. v. To increase the productivity or value of (land or property).
3. v. To put to good use; use profitably.
4. v. To become better.
5. v. To make beneficial additions or changes: improve on the translation.

Century Dictionary and Cyclopedia

1. To make better; ameliorate the condition of; increase in value, excellence, capability, estimation, or the like; bring into a better, higher, more desirable, or more profitable state: as, to improve the mind by study; to improve the breeds of animals; to improve land by careful tillage.
2. To turn to advantage or account; use profitably; make use of: as, to improve an opportunity; to improve the occasion.
3. To increase in force or amount; intensify in any respect.
4. To grow better in any way; become more excellent or more favorable; advance in goodness, knowledge, wisdom, amount, value, etc.: as, his health is improving; the price of cotton improves daily.
5. To increase; grow.
6. To approve; prove; test.
7. To disapprove; censure; blame.
8. To disprove; prove false; refute.

Wiktionary

1. v. to make (something) better; to increase the value or productivity (of something)
2. v. to become better

GNU Webster's 1913

1. v. To disprove or make void; to refute.
2. v. To disapprove; to find fault with; to reprove; to censure.
3. v. To make better; to increase the value or good qualities of; to ameliorate by care or cultivation.
4. v. To use or employ to good purpose; to make productive; to turn to profitable account; to utilize
5. v. To advance or increase by use; to augment or add to; -- said with reference to what is bad.
6. v. To grow better; to advance or make progress in what is desirable; to make or show improvement.
7. v. To advance or progress in bad qualities; to grow worse.
8. v. To increase; to be enhanced; to rise in value.

WordNet 3.0

1. v. get better
2. v. to make better