Girl left one book for a Greek of ancient Italy (7)

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

'left one book for a greek of ancient italy' is the wordplay.
'left one' becomes 'li' (left abbreviation plus i).
'book' becomes 'ot' (I've seen this in other clues).
'for' is a charade indicator (letters next to each other) (I've seen this in other clues).
'a greek of ancient italy' becomes 'ita' (I can't explain this - if you can you should give a lot more credence to this answer).
'li'+'ot'='liot'
'liot' put after 'ita' is 'ITALIOT'.

Can you help me to learn more?