Showering after little time exercising (8)
I believe the answer is:
training
'exercising' is the definition.
(training is a kind of exercising)
'showering after little time' is the wordplay.
'showering' becomes 'raining' (as in showers of rain).
'after' means one lot of letters go next to another.
'little time' becomes 't' (abbreviation for time).
'raining' put after 't' is 'TRAINING'.
(Other definitions for training that I've seen before include "Exercising" , "drill" , "Aiming" , "Instructing, teaching" , "Prepare for a competition or career" .)