Illness being new, complaining more to listeners (9)

I believe the answer is:

pneumonia

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'illness' is the definition.
(pneumonia is a kind of health problem)

I cannot understand how the rest of the clue works.

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(Other definitions for pneumonia that I've seen before include "ailment" , "Inflammation of the lung" , "Lung infection" , "complaint" , "Respiratory disease" .)

I've seen this clue in The Guardian.

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