Ring, as a bell (4)
I believe the answer is:
toll
'ring as a bell' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for toll that I've seen before include "Bridge or road charge" , "Road/bridge charge" , "Ring bell with slow strokes" , "Crossing fee" , "Sum payable to use main road (4)" .)