The aforementioned bit of assault on me (4)
I believe the answer is:
same
'the aforementioned' is the definition.
(thesaurus)
'bit of assault on me' is the wordplay.
'bit of assault' becomes 'sa' (I am not sure about this - if you are sure you should believe this answer much more).
'on' is a charade indicator (letters next to each other).
'sa'+'me'='SAME'
Can you help me to learn more?
(Other definitions for same that I've seen before include "Identical, unchanged" , "Ditto" , "Identical or similar" , "Equal in amount or value" , "Identical, not different" .)