A small hill in South Africa's capital? Not small (5)

I believe the answer is:

kopje

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'a small hill' is the definition.
(I've seen this in another clue)

I don't understand how the rest of the clue works.

(Other definitions for kopje that I've seen before include "South African hill" , "Small hill of S Africa" , "Hillock of South Africa" .)

I've seen this clue in The Independent.

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