In stupid bet about 500 owing (2,4)

I believe the answer is:

in debt

'owing' is the definition.

'in stupid bet about 500' is the wordplay.
'stupid' indicates anagramming the letters (in a stupid order).
'about' says to put letters next to each other.
'500' becomes 'D' (Roman numeral for 500).
'bet' is an anagram of 'ebt'.
'ebt' put after 'd' is 'debt'.
'in'+'debt'='IN DEBT'

(Another definition for in debt that I've seen is " Owing money".)

I've seen this clue in the Sydney Morning Herald.

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