Glitter getting silent treatment (6)
I believe the answer is:
tinsel
'glitter' is the definition.
(thesaurus)
'silent treatment' is the wordplay.
'treatment' is an anagram indicator.
'silent' is an anagram of 'TINSEL'.
'getting' is the link.
(Other definitions for tinsel that I've seen before include "Christmas foil" , "Sparkly strands" , "At Christmas it might be seen" , "superficially attractive" , "Glittering Christmas strip" .)