Hold back and relax before shower (8)
I believe the answer is:
restrain
'hold back' is the definition.
('restrain' can be a synonym of 'hold back')
'relax before shower' is the wordplay.
'relax' becomes 'rest' (I've seen this before).
'before' is a charade indicator (letters next to each other).
'shower' becomes 'rain' ('rain shower' can be a synonym of 'shower').
'rest'+'rain'='RESTRAIN'
'and' is the link.
(Other definitions for restrain that I've seen before include "Keep under control" , "Manacle" , "use handcuffs?" , "stay" , "Tie up - arrest" .)