Moderate anger (6)
I believe the answer is:
temper
I believe this is a double definition.
'moderate' is the first definition.
('temper' can be a synonym of 'moderate')
'anger' is the second definition.
(temper is a kind of anger)
(Other definitions for temper that I've seen before include "Fit of anger - don't lose it" , "State of mind as regards anger (6)" , "Adjust" , "(Calm or furious) disposition" , "Paddy - moderate" .)