He disputes it, with weight (6)
I believe the answer is:
denier
'he disputes it with weight' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'he' is the wordplay.
I cannot really see how this works, but
'he' could be 'den' and 'den' is located in the answer.
The remaining letters 'ier' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for denier that I've seen before include "One unwilling to accept" , "Peter?" , "measure of yarn's quality" , "One refuses to acknowledge" , "Units of weight in silks, nylon and other yarns" .)