A bash in the past (3)

I believe the answer is:

ago

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'in the past' is the definition.
(synonyms)

'a bash' is the wordplay.
'bash' becomes 'go' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'a'+'go'='AGO'

Can you help me to learn more?

(Other definitions for ago that I've seen before include "Earlier, gone by" , "(Years) before the present time" , "Back (in time)" , "Gone, past, since" , "In past times" .)

I've seen this clue in The Daily Mail.

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