A shack of poorish utility (3)
I believe the answer is:
hut
'a shack' is the definition.
(synonyms)
'of poorish utility' is the wordplay.
'of' indicates the answer is hidden within the clue.
'HUT' is hidden within '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" .)