Go no further (4)
'go no further' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stop that I've seen before include "Close < finish" , "Don't allow" , "End or pause" , "Red light signal" , "cut out" .)
(Other definitions for halt that I've seen before include "Stop, small station" , "Small railway station" , "Bring to a stop; lame" , "Pull up" , "game" .)