In his wickedness, there's not much remorse (5)
I believe the answer is:
'much remorse' is the definition.
The definition suggests a singular noun which matches the answer.
'in his wickedness there's not' is the wordplay.
'in' indicates putting letters inside.
'his wickedness' becomes 'sim' (I can't justify this - if you can you should believe this answer much more).
'there's' becomes 'n' (I've seen this in other clues).
'not' becomes 'o' (I've seen this in other clues).
'simn' enclosing 'o' is 'SIMON'.
Can you help me to learn more?
(Other definitions for simon that I've seen before include "disciple" , "Fellow" , "One of Christ's apostles" , "- Templar, The Saint" , "He's simple in rhyme" .)