Exclamation of disgust upon slipping back into the habit (3)

I believe the answer is:

bah

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'exclamation of disgust' is the definition.
(I've seen this in another clue)

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(Other definitions for bah that I've seen before include "Expression of disgust or contempt" , "Appalling!" , "Comic expression of contempt" , "''... Humbug'' Scrooge's cry" , "Exclamation of contempt or disgust - Scrooge used to say it" .)

I've seen this clue in the Evening Standard.

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