Ring - it's taken by robbers (7)
I believe the answer is:
bandits
'robbers' is the definition.
(bandit is a type of robber)
'ring it's taken by' is the wordplay.
'ring' becomes 'band' (synonyms).
'taken by' is a charade indicator (letters next to each other).
'band'+'its'='BANDITS'
(Other definitions for bandits that I've seen before include "'Brigands, outlaws (7)'" , "Violent robbers" .)