Artist has that material (5)
I believe the answer is:
rayon
'material' is the definition.
(type of fabric)
'artist has that' is the wordplay.
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'has' says to put letters next to each other.
'that' becomes 'yon' (archaic term meaning 'that').
'ra'+'yon'='RAYON'
(Other definitions for rayon that I've seen before include "Synthetic fibre" , "No ray (anag)" , "Viscose fabric" , "Or any (anag) -- fibre" , "Synthetic silk-like fabric" .)