Quiet listeners - they need to be sharp (6)

I believe the answer is:

shears

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'they need to be sharp' is the definition.
The definition suggests an adverb but the answer is not.

'quiet listeners' is the wordplay.
'quiet' becomes 'sh' ('sh' is used to tell someone to be quiet).
'listeners' becomes 'ears' (body parts which listen).
'sh'+'ears'='SHEARS'

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(Other definitions for shears that I've seen before include "Garden cutting implement" , "something for lifting loads" , "Cutting instrument" , "Removes fleece" , "Large scissors for shaving sheep" .)

I've seen this clue in The Daily Express.

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