Original sinner given new uniform (4)
I believe the answer is:
even
'uniform' is the definition.
(both can mean equal or level)
'original sinner given new' is the wordplay.
'original sinner' becomes 'eve' (I've seen this in another clue).
'given' means one lot of letters go next to another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'eve'+'n'='EVEN'
(Other definitions for even that I've seen before include "time of day" , "Still - divisible by two" , "Short joke" , "Nearly" , "Regularly; yet" .)