A peremptory refusal by one African people (7)

I believe the answer is:
ashanti
'african people' is the definition.
(I've seen this before)
'a peremptory refusal by one' is the wordplay.
'peremptory refusal' becomes 'shant' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'by' says to put letters next to each other.
'one' becomes 'i' (Roman numeral).
'a'+'shant'+'i'='ASHANTI'
Can you help me to learn more?
(Other definitions for ashanti that I've seen before include "some Africans" , "African people, mainly in Ghana" , "encountered somewhere in Ghana" , "Ghanaians" , "race" .)
