Finish off queen after uprising in African country (5)
I believe the answer is:
niger
'african country' is the definition.
(country in Africa)
'finish off queen after uprising' is the wordplay.
'finish off' means to remove the last letter.
'queen' becomes 'regina' (Latin for 'queen').
'after uprising' is a reversal indicator (in a down clue, letters go up).
'regina' with its last letter taken off is 'regin'.
'regin' back-to-front is 'NIGER'.
'in' acts as a link.
(Other definitions for niger that I've seen before include "West African republic" , "Land-locked country and river of W Africa" , "African river flowing into the South Atlantic" , "River of West Africa" , "one flowing through Mali" .)