Sorry about the failed cake (3)

I believe the answer is:

sad

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'sorry' is the definition.
(I know that sorry can be written as sad)

I don't understand the rest of the clue.

(Other definitions for sad that I've seen before include "Melancholy, triste" , "Melancholy, downhearted" , "Mournful and depressed" , "Deplorable" , "Dejected" .)

I've seen this clue in the Evening Standard.

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