Most intelligent rodent without hesitation in desert (9)

I believe the answer is:

shrewdest

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'most intelligent' is the definition.
Both the answer and definition are superlative adjectives. Maybe they are linked in a way I don't understand?

I can't explain the remainder of the clue.

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(Other definitions for shrewdest that I've seen before include "Most astute or calculating" , "Most crafty and calculating" .)

I've seen this clue in The Guardian.

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