Fail to catch medic before work (4)
I believe the answer is:
drop
'fail' is the definition.
(thesaurus)
'medic before work' is the wordplay.
'medic' becomes 'dr' (doctor).
'before' is a charade indicator (letters next to each other).
'work' becomes 'op' (abbreviation for opus).
'dr'+'op'='DROP'
'to catch' is the link.
(Other definitions for drop that I've seen before include "Discontinue; sink" , "Fall; delivery" , "down, say, casually" , "Small quantity of liquid" , "Fall in small globule" .)