Two short tools for fool (4)

I believe the answer is:

hoax

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

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

(Other definitions for hoax that I've seen before include "Leg-pull" , "Playful fraud" , "Act of deception" , "Deception such as the Piltdown Man" , "Fool" .)

I've seen this clue in The Guardian.

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