Scavenger in middle of Sahara repressing thirst (5)
I believe the answer is:
hyena
'scavenger' is the definition.
(animal which scavenges)
'middle of sahara repressing thirst' is the wordplay.
'middle of' says to take the centre.
'repressing' indicates putting letters inside.
'thirst' becomes 'yen' (yen can mean a craving for something).
The centre of 'sahara' is 'ha'.
'ha' placed around 'yen' is 'HYENA'.
'in' acts as a link.
(Other definitions for hyena that I've seen before include "Dog-like nocturnal mammal of Africa and southern Asia" , "one to laugh" , "Afr. doglike carnivore" , "African native" , "Meat-eater" .)