North African citadel (6)
I believe the answer is:
casbah
'north african citadel' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for casbah that I've seen before include "Market place in N African towns" , "From Arab area" , "Crowded part of old Arab city in N Africa" , "Native quarter of cities in northern Africa" , "North African citadel" .)