They live mainly in the Middle East and North Africa (5)
I believe the answer is:
arabs
'they live mainly in the middle east and north africa' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for arabs that I've seen before include "Graceful horses" , "They live mainly in the Middle East and North Africa" , "Semites" , "eg Saudis" , "Fine horses" .)