Burden of work papers (7)

I believe the answer is:

oppress

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

I cannot understand how the rest of the clue works.

(Other definitions for oppress that I've seen before include "Crush, subjugate" , "Treat harshly" , "Distress" , "Burden" , "Keep in subjection and hardship" .)

I've seen this clue in The Times and The Sun.

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