He refuses a measure of silk (6)
I believe the answer is:
denier
'he refuses a measure of silk' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he refuses a measure' is the wordplay.
'he' becomes 'Den'.
'refuses a measure' becomes 'ier' (I can't explain this - if you can you should believe this answer much more).
'den'+'ier'='DENIER'
Can you help me to learn more?
(Other definitions for denier that I've seen before include "Conspiracist probably" , "old coin" , "Measurement of fineness in silk, nylon etc" , "One refuses to acknowledge" , "measure of yarn's quality" .)