Structures providing poor shelter? (6)
I believe the answer is:
arches
'structures providing' is the definition.
'arches' can be an answer for 'structures' (I've seen this before). I am not sure about the 'providing' bit.
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for arches that I've seen before include "Parts of bridge structure" , "Curved shapes that span openings" , "Curved structures" , "(Cat) stretches (back)" , "Found on feet and bridges" .)