Superficial appearance (6)
I believe the answer is:
veneer
'superficial appearance' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for veneer that I've seen before include "Thin layer glued to a surface" , "Thin layer of fine wood covering surface of cheaper wood" , "Thin coating on the outside" , "Thin wooden facing" , "Thin wooden surface" .)