Stern situation unaffected by a rising (4)

I believe the answer is:

poop

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'stern' is the definition.
('poop' can be a synonym of 'stern')

I don't understand how the rest of the clue works.

(Other definitions for poop that I've seen before include "Tony" , "Palindromic part of a ship" , "Exhaust" , "Fool" , "Deck at the rear of a ship" .)

I've seen this clue in the Evening Standard.

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