... crime syndicate backing plan framing group of footballers (5)
I believe the answer is:
mafia
'crime syndicate' is the definition.
(I've seen this in another clue)
'backing plan framing group of footballers' is the wordplay.
'backing' says the letters should be written in reverse.
'plan' becomes 'aim' (aiming is a kind of planning).
'framing' means one lot of letters goes inside another (inserted letters are framed by the outside letters).
'group of footballers' becomes 'fa' (I am not sure about this - if you are sure you should believe this answer much more).
'aim' placed around 'fa' is 'aifam'.
'aifam' backwards is 'MAFIA'.
Can you help me to learn more?
(Other definitions for mafia that I've seen before include "connection claimed to 23 [JFK]" , "Criminal organisation also known as Cosa Nostra" , "organised criminals" , "Gangsters" , "International crime organisation originating in Sicily" .)