Renouncing a book. Making ineffective (10)

I believe the answer is:

abnegating

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'renouncing' is the definition.
The definition and answer can be both to do with communicating as well as being present participle verbs.
Maybe they are linked in a way I don't understand?

'a book making ineffective' is the wordplay.
'book' becomes 'b' (abbreviation for book).
'making ineffective' becomes 'negating' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'b'+'negating'='ABNEGATING'

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

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