Aussie city: some prosper there (5)
I believe the answer is:
perth
'aussie city' is the definition.
(I've seen this in another clue)
'some prosper there' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'PERTH' is hidden in the letters of 'prosper there'.
(Other definitions for perth that I've seen before include "Capital of Western Australia" , "Town at the head of the Tay estuary" , "Australian state capital" , "Scottish/Australian city" , "Australian or Scottish city" .)