Most of posse fighting with this nasty piece of work could be hopeless (4)

I believe the answer is:

heel

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'most of posse fighting with this nasty piece of work could be hopeless' is the definition.
The definition suggests a singular noun which matches the answer.

This is all the clue.

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(Other definitions for heel that I've seen before include "Not the sole - scoundrel" , "Hindu loincloth" , "Untrustworthy person" , "Slang scoundrel or rear of foot" , "Crusty end of a loaf" .)

I've seen this clue in The Telegraph.

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