Fashion judge's temper (8)
I believe the answer is:
moderate
'temper' is the definition.
('moderate' can be a synonym of 'temper')
'fashion judge's' is the wordplay.
'fashion' becomes 'mode' ('mode' can be a synonym of 'fashion'**).
'judge' becomes 'rate' (rating is a kind of judging).
'mode'+'rate'='MODERATE'
(Other definitions for moderate that I've seen before include "Diminish - within reason" , "Lessen the intensity" , "Read tome (anag) - unexceptional" , "Make reasonable" , "Reduce" .)