Country — one with capital in Abuja (7)

I believe the answer is:

nigeria

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'country' is the definition.
(I know that Nigeria is a country)

'one with capital in abuja' is the wordplay.
'one with' becomes 'niger' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'capital' suggests taking the first letters.
The first letters of 'in abuja' is 'ia'.
'niger'+'ia'='NIGERIA'

Can you help me to learn more?

(Other definitions for nigeria that I've seen before include "In rage I turn to this country" , "West African state" , "part of Africa" , "West African republic" , "W. African country" .)

I've seen this clue in The Sunday Times and The Times.

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