Experts as well as criminals opposing arguments (4,3,4)
I believe the answer is:
pros and cons
'opposing arguments' is the definition.
'pros and cons' can be an answer for 'arguments' (I've seen this before). I am not sure about the 'opposing' bit.
'experts as well as criminals' is the wordplay.
'experts' becomes 'pros' (professionals).
'as well as' becomes 'and' (I've seen this in other clues).
'criminals' becomes 'cons' (short for convicts).
'pros'+'and'+'cons'='PROS AND CONS'
Can you help me to learn more?
(Other definitions for pros and cons that I've seen before include "Groups of dubious characters" , "Arguments for and against" , "Reasons for and against" , "Advantages compared to disadvantages" .)