Dump doctor before work (4)
I believe the answer is:
drop
'dump' is the definition.
(thesaurus)
'doctor before work' is the wordplay.
'doctor' becomes 'dr' ('Dr' can be a synonym of 'doctor'**).
'before' means one lot of letters go next to another.
'work' becomes 'op' (abbreviation for opus).
'dr'+'op'='DROP'
(Other definitions for drop that I've seen before include "Discontinue; sink" , "Fall; delivery" , "Spot" , "Fall (in value)" , "Fall; abandon" .)