Stop in Carshalton (4)
I believe the answer is:
halt
'stop' is the definition.
(synonyms)
'in carshalton' is the wordplay.
'in' indicates the answer is hidden within the clue.
'HALT' is hidden within 'carshalton'.
(Other definitions for halt that I've seen before include "Pull up" , "game" , "Small railway station" , "Falter - stop" , "Stop or pause" .)