Sir belittles lousy writers (11)

I believe the answer is:

belletrists

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'lousy writers' is the definition.
The definition suggests a plural noun which matches the answer.

'sir belittles' is the wordplay.
I cannot quite understand how this works, but
an anagram of 'sir' is 'ris' which is located in the answer.
This explanation may well be incorrect...

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I've seen this clue in the Sydney Morning Herald.

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