Old decorative style, or back to Chanel? (6)
I believe the answer is:
rococo
'old decorative style' is the definition.
'or back to chanel?' is the wordplay.
'back' is a reversal indicator.
'to chanel?' becomes 'coco' (I've seen this in another clue).
'or' in reverse letter order is 'ro'.
'ro'+'coco'='ROCOCO'
(Other definitions for rococo that I've seen before include "Old style of ornamentation" , "Fancy" , "Ornate late baroque style" , "Ornate architectural style" , "Ornamental style associated with Louis XV" .)