Concerning a contest (5)

I believe the answer is:

about

'concerning' is the definition.
(about can mean concerning or relating to)

'a contest' is the wordplay.
'contest' becomes 'bout' (a bout is a boxing match).
'a'+'bout'='ABOUT'

(Other definitions for about that I've seen before include "Apropos, concerning" , "Regarding" , "round" , "Encompassing" , "In conection with, all around" .)

I've seen this clue in The Telegraph and The Daily Express.

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