Skirting hospital, arrive at slum area (6)
I believe the answer is:
ghetto
'slum area' is the definition.
(I've seen this before)
'skirting hospital arrive at' is the wordplay.
'skirting' means one lot of letters goes inside another.
'hospital' becomes 'h'.
'arrive at' becomes 'getto' ('get to' can be a synonym of 'arrive at').
'h' inserted into 'getto' is 'GHETTO'.
(Other definitions for ghetto that I've seen before include "Densely populated city slum" , "In the -- (Elvis Presley)" , "City quarter to which Jewish people were confined" , "Area for those deprived" , "Poor district" .)