Exercise too much without shower in public (5)
I believe the answer is:
overt
'in public' is the definition.
(I've seen this before)
'exercise too much without shower' is the wordplay.
'exercise too much' becomes 'overtrain'.
'without' is a deletion indicator.
'shower' becomes 'rain' (rainfall).
'overtrain' with 'rain' taken out is 'OVERT'.
(Other definitions for overt that I've seen before include "not disguised" , "Open, not secret or hidden" , "____ is able to be seen" , "Open and observable" , "Open,up front" .)