Desert that covers most of North Africa (6)
I believe the answer is:
sahara
'desert that covers most of north africa' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sahara that I've seen before include "Great desert in N Africa" , "Great African desert" , "World's largest sandy area" , "Uncultivated region of north Africa" , "World's largest desert" .)