Impudence by lecturer he doesn't need to hear (9)

I believe the answer is:

lipreader

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'he doesn't need to hear' is the definition.
I know nothing about this answer so I cannot judge whether this works.

'impudence by lecturer' is the wordplay.
'impudence' becomes 'lip' (lip is a kind of impudence).
'by' means one lot of letters go next to another.
'lecturer' becomes 'reader' (synonyms).
'lip'+'reader'='LIPREADER'

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I've seen this clue in The Daily Express.

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