Get cracking, ages ago (3)

I believe the answer is:

hie

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'get cracking' is the definition.
(I've seen this in another clue)

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for hie that I've seen before include "Hasten" , "Hurry" , "Make one's way quickly" , "Be quick (lit.)" , "Go quickly (archaic)" .)

I've seen this clue in the Evening Standard.

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