Young predator put away — copper goes by book (4,3)

I believe the answer is:

wolf cub

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'young predator' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for wolf cub that I've seen before include "old junior Scout" , "Young carnivore" , "Young scout" , "one of six as previously named" , "one of Mowgli's brothers" .)

I've seen this clue in The Guardian.

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