Professional criminal's staff (5)

I believe the answer is:

crook

I believe this is a double definition.

'professional criminal's' is the first definition.
(I've seen this before)

'staff' is the second definition.
(a crook is a shepherd's staff)

(Other definitions for crook that I've seen before include "Hooked staff" , "Fence, perhaps" , "Shepherd's staff" , "Swindler - crosier - ill (in Australia)" , "Well, no" .)

I've seen this clue in The Telegraph.

Want a hint initially instead of a full solution? Install my app