To become sharp.
To make sharp.
To become warmer.
To reach, or cause to reach, a normal operating temperature (of a car for example).
To heat or reheat (e.g. food).
To do gentle exercise, stretching etc., in order to prepare the body for more vigorous exercise.
To make (an audience) enthusiastic or animated before a show
To prepare for an activity by carrying out a practice or preparation routine.