A good look round South African city (5)
I believe the answer is:
lagos
'african city' is the definition.
(Nigerian city)
'a good look round south' is the wordplay.
'a good' becomes 'ag' (I've seen this in other clues**).
'look' becomes 'lo'.
'round' means one lot of letters goes inside another.
'south' becomes 's' ('S' can be a synonym of 'south').
'ag' put within 'lo' is 'lago'.
'lago'+'s'='LAGOS'
(Other definitions for lagos that I've seen before include "Chief port and former capital of Nigeria" , "Former Nigerian capital" , "Formerly capital of Nigeria" , "city in Africa" , "Nigerian city and port" .)