A shack in south Utah (3)
I believe the answer is:
hut
'a shack' is the definition.
('hut' can be a synonym of 'shack')
'in south utah' is the wordplay.
'in' indicates a hidden word.
'HUT' is hidden in the letters of 'south utah'.
(Other definitions for hut that I've seen before include "Small house, shed" , "Small wooden shelter" , "Simple dwelling" , "Small, simple shelter" , "Small shed for storing, say, garden tools" .)