Crossword Genius

Quitting and filling suitcase (7,2)

Ross

I believe the answer is:

packing up

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'suitcase' is the definition.
I know nothing about this answer so I can't judge whether it can be defined by this definition.

'quitting and filling' is the wordplay.
'quitting' becomes 'up' (I can't explain this - if you can you should believe this answer much more).
'and' is a charade indicator (letters next to each other).
'filling' becomes 'packing' (packing is a kind of filling).
'up' after 'packing' is 'PACKING UP'.

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I've seen this clue in The Daily Express.
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