Moderate rage (6)
I believe the answer is:
temper
I believe this is a double definition.
'moderate' is the first definition.
(I know that moderate can be written as temper)
'rage' is the second definition.
(temper means anger or rage)
(Other definitions for temper that I've seen before include "Harden metal by heating and cooling" , "Irritability" , "Paddy - moderate" , "Tendency to become angry easily" , "Lose it and lose control" .)