Was model wearing shiny fabric? (5)
I believe the answer is:
satin
'shiny fabric?' is the definition.
(I've seen this before)
'was model wearing' is the wordplay.
'was model' becomes 'sat' (to sit is to model for a painting).
'wearing' becomes 'in' (in jeans or in a dress).
'sat'+'in'='SATIN'
(Other definitions for satin that I've seen before include "Silky material" , "Stain found in cloth" , "Rich cloth" , "covered with?" , "Fine material" .)