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Swear model falls for b------, ideally (2,4)

Ross

I believe the answer is:

at best

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'ideally' is the definition.
(thesaurus)

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(Other definitions for at best that I've seen before include "In the most optimistic situation" , "In the optimum situation" , "Under optimum conditions" , "the most you can expect" , "In the most favourable outcome" .)

I've seen this clue in the Sydney Morning Herald.
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