Naïf, amazingly, exposes regressively ruthless organisation (5)
I believe the answer is:
mafia
'ruthless organisation' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.
'naif amazingly exposes regressively' is the wordplay.
'MAFIA' is hidden backwards in amongst the letters.
However, I am uncertain how this is indicated.
Can you help me to learn more?
(Other definitions for mafia that I've seen before include "Secret criminal organisation" , "Criminal organisation also known as Cosa Nostra" , "Sicilian one" , "Sicilian criminal body" , "Gangsters" .)