Loses girl over bet (7)

I believe the answer is:

mislays

'loses' is the definition.
('mislay' can be a synonym of 'lose')

'girl over bet' is the wordplay.
'girl' becomes 'miss' (term of address for an unmarried woman).
'over' indicates putting letters inside.
'bet' becomes 'lay' (lay bet is a type of bet in gambling).
'miss' enclosing 'lay' is 'MISLAYS'.

(Another definition for mislays that I've seen is " Puts in wrong place, loses".)

I've seen this clue in The Guardian.

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