West African republic; capital Niamey (5)
I believe the answer is:
niger
This clue is a double definition.
'west african republic' is the first definition.
(I've seen this in another clue)
'capital niamey' is the second definition.
(I know that Niger capital Niamey)
(Other definitions for niger that I've seen before include "one flowing through Mali" , "River of West Africa" , "Country W. of Chad" , "Country in interior of N Africa, capital Niarney" , "W. African country" .)