Idiot has to stop detaining fine all-female group (7)
I believe the answer is:
halfwit
'idiot' is the definition.
(both can mean a stupid person)
'to stop detaining fine all-female group' is the wordplay.
'to stop' becomes 'halt' (halt can mean to stop).
'detaining' means one lot of letters goes inside another.
'fine all' becomes 'f' (I can't explain this - if you can you should believe this answer much more).
'female group' becomes 'WI' (Women's Institute).
'f'+'wi'='fwi'
'halt' placed around 'fwi' is 'HALFWIT'.
'has' is the link.
Can you help me to learn more?
(Other definitions for halfwit that I've seen before include "Mug" , "Charlie?" , "Idiot" , "Being stupid" , "dunce?" .)