sharpen

verb

1.
make sharp or sharper
Antonym:
dull
Derived from:
sharpener
Instrument:
sharpener
2.
make crisp or more crisp and precise
3.
become sharp or sharper
4.
put (an image) into focus
5.
make (images or sounds) sharp or sharper
Antonym:
soften
6.
raise the pitch of (musical notes)
Antonym:
flatten
7.
8.
make (one's senses) more acute