One of sharp righteous nature? (4)

I believe the answer is:

prig

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'one of sharp righteous nature?' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps you can see an association between them that I can't see?

'of sharp righteous nature?' is the wordplay.
'of' indicates the answer is hidden within the clue.
'PRIG' is hidden within 'sharp righteous nature'.

Can you help me to learn more?

(Other definitions for prig that I've seen before include "Goody-goody" , "Prude" , "Stuffed shirt" , "Old maid" , "Self-righteous moralist" .)

I've seen this clue in The Globe and Mail.

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