Medic approaching sailor’s bunk (5)
I believe the answer is:
dross
'bunk' is the definition.
(both can mean rubbish)
'medic approaching sailor's' is the wordplay.
'medic' becomes 'dr' (doctor).
'approaching' is a charade indicator (letters next to each other).
'sailor's' becomes 'oss' (ordinary seaman).
'dr'+'oss'='DROSS'
(Other definitions for dross that I've seen before include "Waste coal - rubbish" , "Scum on molten metals" , "Scum - dregs" , "Lees" , "Worthless stuff" .)