Group of stars with capital American attorney (9)
I believe the answer is:
andromeda
'group of stars' is the definition.
(Andromeda is a constellation)
'with capital american attorney' is the wordplay.
'with' becomes 'and'.
'capital' becomes 'Rome' (capital of Italy).
'american attorney' becomes 'DA' (abbreviation for District Attorney).
'and'+'rome'+'da'='ANDROMEDA'
(Other definitions for andromeda that I've seen before include "Pattern of stars" , "plant" , "group of stars" , "Large northern constellation between Perseus and Pegasus" , "she was given a starring role" .)