Hard work one gets very much upset about (4)

I believe the answer is:

toil

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'hard work' is the definition.
(I've seen this in another clue)

I don't understand the remainder of the clue.

(Other definitions for toil that I've seen before include "Manual labour" , "Work hard and long" , "Work hard, labour" , "Hard physical work" , "Drudgery" .)

I've seen this clue in The Globe and Mail.

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