Such a worker hasn't got all day (4,4)

I believe the answer is:

part time

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'such' is the definition.
Both the definition and answer are adjectives. Perhaps you can see an association between them that I don't see?

I cannot understand how the rest of the clue works.

Can you help me to learn more?

(Other definitions for part time that I've seen before include "Not working a full week" , "One may find some workers like this" , "temp?" , "Not fully committed" .)

I've seen this clue in the Evening Standard.

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