Curb others having shower ahead of time (9)
I believe the answer is:
restraint
'curb' is the definition.
(I've seen this before)
'others having shower ahead of time' is the wordplay.
'others' becomes 'rest' (I've seen this in other clues).
'having' says to put letters next to each other.
'shower' becomes 'rain' (synonyms).
'ahead of time' becomes 't' (I've seen this in other clues).
'rest'+'rain'+'t'='RESTRAINT'
(Other definitions for restraint that I've seen before include "Controlling measure" , "Reserve" , "It keeps someone or something under control" , "Curb" , "Check" .)