verb (v)

• make sharp or sharper(verb.contact)

  Example:
  Sharpen the knives.
  

  Antonym:
  blunt, dull
  

  source: wordnet30
• make crisp or more crisp and precise(verb.change)

  Example:
  We had to sharpen our arguments.
  

  source: wordnet30
• become sharp or sharper(verb.change)

  Example:
  The debate sharpened.
  

  source: wordnet30
• put (an image) into focus(verb.change)

  Synonym:
  focalise, focalize, focus
  Antonym:
  blear, blur
  

  source: wordnet30
• make (images or sounds) sharp or sharper(verb.perception)

  Antonym:
  soften
  

  source: wordnet30
• raise the pitch of (musical notes)(verb.change)

  Antonym:
  drop, flatten
  

  source: wordnet30
• give a point to(verb.change)

  Synonym:
  point, taper
  

  source: wordnet30
• make (one's senses) more acute(verb.change)

  Example:
  This drug will sharpen your vision.
  

  Synonym:
  heighten
  

  source: wordnet30
• To make sharp.(verb)

  source: webster1913
• To grow or become sharp.(verb)

  source: webster1913