Bounder sensible to restrain anger? This isn't too heated (4,11)
I believe the answer is:
room temperature
'this isn't too heated' is the definition.
The definition suggests a singular noun which matches the answer.
'bounder sensible to restrain anger?' is the wordplay.
'bounder' becomes 'roo' (short for kangaroo, something which bounds).
'sensible' becomes 'mature' (I've seen this before).
'to restrain' means one lot of letters goes inside another.
'anger?' becomes 'temper' (temper is a kind of anger).
'mature' placed around 'temper' is 'mtemperature'.
'roo'+'mtemperature'='ROOM TEMPERATURE'
Can you help me to learn more?
(Other definitions for room temperature that I've seen before include "around seventy" , "not very heated" , "Degree of heat" .)