Opening sideboard, where one can arrange goods in a stylish way (6,7)
I believe the answer is:
window dresser
'where one can arrange goods in a stylish way' is the definition.
Although both the answer and definition are singular nouns, I cannot see how they can define each other.
'opening sideboard' is the wordplay.
'opening' becomes 'window' (a window is an opening).
'sideboard' becomes 'dresser' (I've seen this before).
'window'+'dresser'='WINDOW-DRESSER'
Can you help me to learn more?
(Other definitions for window dresser that I've seen before include "Person who arranges shop front displays" , "Shop display arranger" , "Shopfront decorator" , "Shop front display organiser" , "Shop display creator" .)