Boxer on about one expelling much gas (8)

I believe the answer is:

jabberer

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'one expelling much gas' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.

'boxer on about' is the wordplay.
'boxer' becomes 'jabber' (I can't explain this - if you can you should believe this answer much more).
'on' indicates putting letters inside (as in clothing 'on' a person).
'about' becomes 're' ('re' means regarding or about).
'jabber' placed around 're' is 'JABBERER'.

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I've seen this clue in The Sunday Times and The Times.

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