Ostentatious clothing (6)
I believe the answer is:
finery
'ostentatious clothing' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for finery that I've seen before include "Regalia" , "Showy clothing" , "Elaborate clothing, jewellery etc" , "Elaborate clothes and accessories" , "Fancy clothes or trappings" .)