New on street, work without break (3-4)
I believe the answer is:
non-stop
'without break' is the definition.
'new on street work' is the wordplay.
'new' becomes 'n'.
'street' becomes 'st'.
'work' becomes 'op' (abbreviation for opus).
'n'+'on'+'st'+'op'='NON-STOP'
(Other definitions for non-stop that I've seen before include "Uninterrupted" , "Ceaseless" , "Round-the-clock" , "Going straight from A to B" , "Continuous" .)