To make or become sharp or sharper. He used a whetstone to sharpen the knife.
To improve or enhance a skill or ability. She took extra classes to sharpen her math skills.
To make a point or argument more precise or clear. The lawyer sharpened his argument before presenting it in court.
To increase the focus or clarity of an image or sound. The editor used software to sharpen the image for the magazine.
(Music) To raise the pitch of (a note) by a semitone. The accidental in the score sharpens the C, making it C-sharp.