A bit furtive, this little animal? (4)

I believe the answer is:

mink

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'animal?' is the definition.
(thesaurus)

I cannot understand how the remainder of the clue works.

(Other definitions for mink that I've seen before include "Animal with valued fur" , "(Fur from) small carnivore" , "(Animal prized for its) fur" , "Animal farmed for fur" , "Animal of weasel family with highly-valued fur" .)

I've seen this clue in the Evening Standard.

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