Criminals direct round over a Fed’s head (5)
I believe the answer is:
mafia
'criminals' is the definition.
(I've seen this before)
'direct round over a fed's head' is the wordplay.
'direct' becomes 'aim' (synonyms).
'round' shows that the letters should be reversed in order.
'over' means one lot of letters goes inside another.
'head' suggests taking the first letters.
The initial letter of 'feds' is 'f'.
'aim' in reverse letter order is 'mia'.
'a'+'f'='af'
'mia' placed around 'af' is 'MAFIA'.
(Other definitions for mafia that I've seen before include "Sicilian criminal body" , "Secret criminal organisation" , "Sicilian criminal organisation" , "Group exerting a hidden sinister influence" , "Criminal organisation also known as Cosa Nostra" .)