Outlaw group over it (6)
I believe the answer is:
bandit
'outlaw' is the definition.
(bandit is a kind of outlaw)
'group over it' is the wordplay.
'group' becomes 'band' (band can mean a group of people).
'over' means one lot of letters go next to another.
'band'+'it'='BANDIT'
(Other definitions for bandit that I've seen before include "Violent outlaw" , "Thief" , "Outlawed robber" , "Outlaw, robber" , "Highwayman" .)