Fashionably anachronistic (5)
I believe the answer is:
retro
'fashionably anachronistic' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for retro that I've seen before include "Imitative of past styles" , "Looking backwards" , "recapturing the past" , "Imitative of a style from the recent past" , "Imitative of an older style" .)