Shed unfashionable stockings worn by upper class (8)
I believe the answer is:
outhouse
'shed' is the definition.
(I've seen this before)
'unfashionable stockings worn by upper class' is the wordplay.
'unfashionable' becomes 'out' (similar in meaning).
'stockings' becomes 'hose' (hose refers to stockings, tights etc).
'worn by' means one lot of letters goes inside another (outside letters are worn by those on the inside).
'upper class' becomes 'u' (as in U- and non-U speech).
'hose' placed around 'u' is 'house'.
'out'+'house'='OUTHOUSE'
(Other definitions for outhouse that I've seen before include "External building" , "Building in the grounds of a house" , "Smaller building separate from main one" , "Shed or barn belonging to house but not part of it" , "Construction" .)