African shelter on base of plateau (4)
I believe the answer is:
hutu
'african' is the definition.
(I've seen this before)
'shelter on base of plateau' is the wordplay.
'shelter' becomes 'hut' (hut is a kind of shelter**).
'on' means one lot of letters go next to another.
'base of' indicates one should take the final letters.
The last letter of 'plateau' is 'u'.
'hut'+'u'='HUTU'
(Other definitions for hutu that I've seen before include "A member of one Rwandan people" , "Bantu speaker from Rwanda or Burundi" , "Member of a Bantu people living in Rwanda and Burundi" , "Africans" , "Rwandan or Burundian" .)