Doctor with private swamp (5)
I believe the answer is:
drown
'swamp' is the definition.
(I've seen this before)
'doctor with private' is the wordplay.
'doctor' becomes 'dr' (abbreviation).
'with' says to put letters next to each other.
'private' becomes 'own' (as in one's own or private belongings).
'dr'+'own'='DROWN'
(Other definitions for drown that I've seen before include "Immerse (fatally?)" , "Die in water" , "Swamp" , "Flood (an area)" , "Die by inhaling liquid" .)