at exactly 10.30, 2.00 etc:
We're meeting at one-thirty sharp.
2 British English
if you turn sharp left or right, you make a sudden change of direction to the left or right:
You turn sharp right at the crossroads.
3 British English old-fashioned
used to tell someone to do something quickly:
If you look sharp you might catch him before he leaves for London.
played or sung at a slightly higher pitch than is correct [↪ flat]