Stole pig with rook making escape (3)

I believe the answer is:

boa

I'm a little stuck... Click here to teach me more about this clue!

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

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

(Other definitions for boa that I've seen before include "... cold-blooded creature" , "Python" , "One covered in scales" , "One with scaly body" , "Wrap" .)

I've seen this clue in The Independent.

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