Don't keep? Nonsense! (3)

I believe the answer is:

rot

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This could be a double definition.

'don't keep?' is the first definition.
The definition suggests a singular noun which matches the answer.

'nonsense' is the second definition.
(I've seen this before)

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(Other definitions for rot that I've seen before include "Balderdash" , "Decay in grotesque way" , "Rubbish (colloq.)" , "Decay, moulder" , "Codswallop" .)

I've seen this clue in the Evening Standard.

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