Only fancy new material (5)
I believe the answer is:
nylon
'material' is the definition.
(nylon is a kind of material)
'only fancy new' is the wordplay.
'fancy' indicates anagramming the letters.
'new' becomes 'n'.
'only' is an anagram of 'nylo'.
'nylo'+'n'='NYLON'
(Other definitions for nylon that I've seen before include "Fibrous material" , "Tough synthetic material" , "may be damaged by running" , "Synthetic cloth" , "Synthetic material used in textiles" .)