Istanbul a way off interior African city (8)
I believe the answer is:
bulawayo
'african city' is the definition.
(second largest city in Zimbabwe)
'istanbul a way off interior' is the wordplay.
'interior' indicates the answer is hidden within the clue (I've seen 'interior of' mean this).
'BULAWAYO' can be found hidden inside 'istanbul a way off'.
(Other definitions for bulawayo that I've seen before include "Industrial city of Zimbabwe" , "African city" .)