Any number knowing about fine material (5)
I believe the answer is:
ninon
'fine material' is the definition.
(I've seen this before)
'any number knowing' is the wordplay.
'any number' becomes 'n' (I've seen this in other clues).
'knowing' becomes 'inon' (I've seen this before).
'n'+'inon'='NINON'
'about' is the link.
(Other definitions for ninon that I've seen before include "Fine, strong, silky fabric" , "fine material" , "Lightweight silk fabric" , "Fine sheer fabric" , "thin fabric" .)