High-grade carpet fiber (5)
I believe the answer is:
sisal
'high-grade carpet fiber' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for sisal that I've seen before include "Rope fibre from leaves of tropical plant" , "material for painter, say?" , "Natural fibre" , "Fibrous plant used for rope" , "Fibre-yielding plant" .)