at some time sharp

at (some time) sharp

At an exact time, with the emphasis that one must not be late. We need to leave for the airport at 8 AM sharp tomorrow morning. Please be here at 6:30 sharp.
See also: sharp

at some time sharp

exactly at the time named. You must be here at noon sharp. The plane is expected to arrive at seven forty-five sharp.
See also: sharp, time