Cutting time on ring road fellow circles (7)
I believe the answer is:
mordant
'cutting' is the definition.
(thesaurus)
'time on ring road fellow circles' is the wordplay.
I cannot really understand how this works, but
'time' could be 't' (abbreviation) and 't' is found within the answer.
'ring' could be 'o' (letter resembling a ring) and 'o' is found in the answer.
'road' could be 'rd' (abbreviation) and 'rd' is present in the answer.
'fellow' could be 'man' (fellow can mean a man) and 'man' is located in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for mordant that I've seen before include "(Of wit) sharp, critical" , "Acerbic" , "Waspish" , "Bitingly sarcastic" , "Caustic" .)