Prosecuted about it but satisfied (6)
I believe the answer is:
suited
'but satisfied' is the definition.
The definition and answer can be both to do with fundamental existence as well as being past participle verbs.
Perhaps they are linked in a way I don't understand?
'prosecuted about it' is the wordplay.
'prosecuted' becomes 'sued' (I've seen this before).
'about' is an insertion indicator.
'sued' placed around 'it' is 'SUITED'.
Can you help me to learn more?
(Other definitions for suited that I've seen before include "Well adapted" , "Appropriate, fitting" , "Matched" , "Was convenient to" , "agreed" .)