Crossword Genius

Posh girl upset by model runs away (4,2)

Ross

I believe the answer is:

legs it

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'runs away' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'posh girl upset by model' is the wordplay.
'posh girl' becomes 'gel' (I've seen this in other clues).
'upset' is a reversal indicator.
'by' says to put letters next to each other.
'model' becomes 'sit' (e.g. for a painting).
'gel' in reverse letter order is 'leg'.
'leg'+'sit'='LEGS IT'

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I've seen this clue in The Times.
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