Dissolute man in a swamp city (9)
I believe the answer is:
marrakesh
'city' is the definition.
(I have seen 'African city' mean 'marrakesh' so perhaps 'city' could also mean 'marrakesh')
'dissolute man in a swamp' is the wordplay.
'dissolute man' becomes 'rake' (I've seen this before).
'in' means one lot of letters goes inside another.
'a swamp' becomes 'marsh' (I've seen this before).
'rake' put within 'marsh' is 'MARRAKESH'.
(Other definitions for marrakesh that I've seen before include "in North Africa" , "city abroad" , "city in Africa" , "African city" .)