Jacket in retro Chanel style (6)
I believe the answer is:
rococo
'style' is the definition.
(I've seen this before)
'jacket in retro chanel' is the wordplay.
'jacket in' means to remove the middle letters (outside letters form the word's 'jacket').
'chanel' becomes 'coco' (I've seen this in other clues).
'retro' with its middle taken out is 'ro'.
'ro'+'coco'='ROCOCO'
(Other definitions for rococo that I've seen before include "Tastelessly florid" , "showing lots of curves?" , "Eighteenth-century French architectural style" , "Ornate late baroque style" , "Delicate architectural style from 18th-century France" .)