Being worn, they won't work (4)

I believe the answer is:

duds

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'won't work' is the definition.
I can't tell whether this defines the answer.

'being worn they' is the wordplay.
'being' becomes 'dud' (dud is a kind of being).
'worn they' becomes 's' (I can't justify this - if you can you should give a lot more credence to this answer).
'dud'+'s'='DUDS'

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(Other definitions for duds that I've seen before include "Failures; clothes" , "Bombs that fail to explode" , "One assumes them" .)

I've seen this clue in the Evening Standard.

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