A shack of poorish utility (3)
I believe the answer is:
hut
'a shack' is the definition.
('hut' can be a synonym of 'shack')
'of poorish utility' is the wordplay.
'of' says the answer is hidden in the clue.
'HUT' is hidden in the letters of 'poorish utility'.
(Other definitions for hut that I've seen before include "Simple dwelling" , "Small shed for storing, say, garden tools" , "Small roughly-made house or shelter" , "Simple house or shelter" , "Small wooden shelter" .)