Mild casual worker endlessly subjected to censure (9)
I believe the answer is:
temperate
'mild' is the definition.
('temperate' can be similar in meaning to 'mild')
'casual worker endlessly subjected to censure' is the wordplay.
'casual worker' becomes 'temp' (I've seen this before).
'endlessly' says to take the centre (the ends of the words are removed).
'to censure' becomes 'rate'.
The middle of 'subjected' is 'e'.
'temp'+'e'+'rate'='TEMPERATE'
(Other definitions for temperate that I've seen before include "with balmy climate" , "It is reasonable" , "Controlled" , "sober" , "With mild climate" .)