sharpen

make sharp or sharper; "sharpen the knives"

make crisp or more crisp and precise; "We had to sharpen our arguments"

become sharp or sharper; "The debate sharpened"

put (an image) into focus; "Please focus the image; we cannot enjoy the movie"

make (images or sounds) sharp or sharper

raise the pitch of (musical notes)

give a point to; "The candles are tapered"

make (one's senses) more acute; "This drug will sharpen your vision"