A lot of lustrous fabric, so shiny (7)
I believe the answer is:
silvery
'shiny' is the definition.
'a lot of lustrous fabric so' is the wordplay.
'a lot of' means to remove the last letter (a lot of the word but not all of it).
'lustrous fabric' becomes 'silk' (I've seen this in another clue).
'so' becomes 'very' (I've seen this before).
'silk' with its final letter taken away is 'sil'.
'sil'+'very'='SILVERY'
(Other definitions for silvery that I've seen before include "Having a white lustrous sheen, like the Spire" , "like a mirror?" , "having clear rings?" , "Elementary description of moon" , "Epithet for the moon" .)