Endorse heist? Government punishing (4-8)

I believe the answer is:

back-breaking

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'punishing' is the definition.
(synonyms)

'endorse heist? government' is the wordplay.
'endorse' becomes 'back' (synonyms).
'heist? government' becomes 'breaking' (I am not sure about this - if you are sure you should believe this answer much more).
'back'+'breaking'='BACK-BREAKING'

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

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