Material that's light to put on (5)
I believe the answer is:
rayon
'material' is the definition.
(I know that Rayon is a type of material)
'light to put on' is the wordplay.
'light' becomes 'ray' (ray is a kind of light).
'to put' is a charade indicator (letters next to each other).
'ray'+'on'='RAYON'
'that's' acts as a link.
(Other definitions for rayon that I've seen before include "Man-made fibre" , "Synthetic silk-like fabric" , "Artificial silk fabric" , "Artificial fibre" , "Man-made fabric" .)