Crossword Genius

Having done, he's said to want paying (3)

Ross

I believe the answer is:

dun

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'having done he's said to want paying' is the definition.
Although both the answer and definition are singular nouns, I can't understand how one could define the other.

This is the entire clue.

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(Other definitions for dun that I've seen before include "Pursue or badger for debt" , "Press for payment" , "Dingy brown" , "Dull brownish-grey colour" , "nag, for payment" .)

I've seen this clue in the Evening Standard.
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