verb (v)

• to make better(verb.change)

  Example:
  The editor improved the manuscript with his changes.
  

  Synonym:
  ameliorate, amend, better, meliorate
  Antonym:
  aggravate, exacerbate, exasperate, worsen
  

  source: wordnet30
• get better(verb.change)

  Example:
  The weather improved toward evening.
  

  Synonym:
  ameliorate, better, meliorate
  Antonym:
  decline, worsen
  

  source: wordnet30
• To disprove or make void; to refute.(verb)

  source: webster1913
• To make better; to increase the value or good qualities of; to ameliorate by care or cultivation; as, to improve land.(verb)

  source: webster1913
• To grow better; to advance or make progress in what is desirable; to make or show improvement; as, to improve in health.(verb)

  source: webster1913