Safe temperature, equal all round (5)
I believe the answer is:
peter
'safe' is the definition.
(I've seen this in other clues)
'temperature equal all round' is the wordplay.
'temperature' becomes 't' (abbreviation).
'equal' becomes 'peer' ('peer' can be a synonym of 'equal'**).
'all round' is an insertion indicator.
't' placed into 'peer' is 'PETER'.
(Other definitions for peter that I've seen before include "and 14 dn Latest actor to play Doctor Who" , "foundation for church" , "Fellow < safe" , "One of the Apostles" , "Safe; saint" .)