Good-for-nothing cryptic clues, no way to break in (9)

I believe the answer is:

scoundrel

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'good-for-nothing' is the definition.
(thesaurus)

I cannot understand how the rest of the clue works.

(Other definitions for scoundrel that I've seen before include "Untrustworthy figure" , "Rascal" , "Red consul may be a rogue" , "Rat" , "Cad" .)

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