Gloomy bishop opening church bazaar? (5)
I believe the answer is:
sable
'gloomy' is the definition.
(thesaurus)
'bishop opening church bazaar?' is the wordplay.
'bishop' becomes 'B' (abbreviation used in chess).
'opening' means one lot of letters goes inside another (some letters open a gap in others).
'church bazaar?' becomes 'sale' (a church bazaar is a sale).
'b' placed inside 'sale' is 'SABLE'.
(Other definitions for sable that I've seen before include "Bales of valuable Russian fur" , "Marten's fur - dark black" , "Dark brown fur of the marten" , "Black (heraldry); fur" , "Black; antelope" .)