Don't continue work at the bottom of the street (4)
I believe the answer is:
stop
'don't continue' is the definition.
(I've seen this in another clue)
'work at the bottom of the street' is the wordplay.
'work' becomes 'op' (abbreviation for opus).
'at the bottom of' means one lot of letters go next to another (in a down clue, some letters go below others).
'the street' becomes 'st' (abbreviation).
'op' put after 'st' is 'STOP'.
(Other definitions for stop that I've seen before include "Bung" , "high card in bridge" , "Don't allow" , "Intercept" , "Part of organ" .)