Apprentice showers in driving area (7)
I believe the answer is:
trainee
'apprentice' is the definition.
(someone undergoing training)
'showers in driving area' is the wordplay.
'showers' becomes 'rain' (rain showers).
'in' is an insertion indicator.
'driving area' becomes 'tee' (a golfer drives a golf ball from a tee).
'rain' put inside 'tee' is 'TRAINEE'.
(Other definitions for trainee that I've seen before include "One being taught a job" , "One undergoing instruction" , "novice" , "21 [TYRO]" , "One being instructed" .)