A success despite the audio fault (3)

I believe the answer is:

wow

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'a success' is the definition.
(I have seen 'Huge success' mean 'wow' so perhaps 'success' could also mean 'wow')

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

Can you help me to learn more?

(Other definitions for wow that I've seen before include "that's incredible!" , "Expression of surprised admiration" , "Expression of great admiration" , "Impress hugely" , "Great success" .)

I've seen this clue in the Evening Standard.

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