Dump building outside (4)
I believe the answer is:
shed
This might be a double definition.
'dump' is the first definition.
(I've seen this before)
'building outside' is the second definition.
'shed' can be an answer for 'building' (I've seen this before). I am not certain of the 'outside' bit.
Can you help me to learn more?
(Other definitions for shed that I've seen before include "Abandoned" , "Hut - throw off - Guardian cryptic crossword setter" , "Simple building; discard" , "storage facility" , "dropped" .)