Exhausted and stuck in the mud? (6)

I believe the answer is:

rooted

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'exhausted' is the definition.
Both the definition and answer are adjectives. Maybe you can see a link between them that I can't see?

I cannot understand how the remainder of the clue works.

Can you help me to learn more?

(Other definitions for rooted that I've seen before include "Fixed to the spot like a plant" , "Frivolousness" , "Firmly attached as plants are to ground" , "Deeply felt" , "Stuck to the spot" .)

I've seen this clue in the Sydney Morning Herald.

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