Shiny metal (6)
I believe the answer is:
chrome
'shiny metal' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for chrome that I've seen before include "A yellow colouring matter" , "Decorative plating" , "Shiny metal for plating" , "Protective finish on motor vehicle fittings" , "Feature of bath taps" .)