Quibble with returning metal tool (7)
I believe the answer is:
nitpick
'quibble' is the definition.
(thesaurus)
'with returning metal tool' is the wordplay.
'with' is a charade indicator (letters next to each other).
'returning' shows that the letters should be reversed in order.
'metal' becomes 'tin' (tin is a kind of metal).
'tool' becomes 'pick' (pick is a kind of tool).
'tin' in reverse letter order is 'nit'.
'nit' next to 'pick' is 'NITPICK'.
(Other definitions for nitpick that I've seen before include "Find little fault" , "Be fussy and pedantic" , "Make petty criticism" , "Find fault in petty way" , "Find fault fussily" .)