Breaking under the hammer? (5)

I believe the answer is:

going

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'breaking' is the definition.
('go' can be a synonym of 'break')

I can't explain the rest of the clue.

(Other definitions for going that I've seen before include "Due to leave" , "It affects runners" , "attending" , "fading" , "Ground condition for horse racing" .)

I've seen this clue in the Evening Standard.

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