Weight of material one refuses to acknowledge (6)
I believe the answer is:
denier
'one refuses to acknowledge' is the definition.
(I've seen this before)
I don't understand the rest of the clue.
Can you help me to learn more?
(Other definitions for denier that I've seen before include "One who repudiates" , "One refusing to face facts" , "Measurement of fineness in silk, nylon etc" , "Person refusing to admit (something)" , "One who doesn't believe" .)