Burden hanging over setter and solver (4)

I believe the answer is:

onus

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'burden' is the definition.
(synonyms)

'hanging over setter and solver' is the wordplay.
'hanging over' becomes 'on' (physically on top of. I am not sure about the 'hanging' bit.).
'setter and solver' becomes 'us' (the setter and the solver of the crossword).
'on'+'us'='ONUS'

Can you help me to learn more?

(Other definitions for onus that I've seen before include "'Burden, of proof (4)'" , "Obligation - charge" , "albatross?" , "Capulet opponent (R&J)" , "Duty or responsibility" .)

I've seen this clue in The Everyman puzzle in The Observer.

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