Fur bishop found in auction (5)
I believe the answer is:
sable
'fur' is the definition.
(I know that sable is a fur)
'bishop found in auction' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'found in' is an insertion indicator.
'auction' becomes 'sale' (type of sale).
'b' inserted inside 'sale' is 'SABLE'.
(Other definitions for sable that I've seen before include "North Asian marten" , "Bales (anag.)" , "Fur from member of weasel family" , "(Fur from) small carnivore" , "Black (heraldry); fur" .)