Empty space found by one Italian beside French lake! (6)
I believe the answer is:
lacuna
'empty space' is the definition.
(I've seen this in another clue)
'one italian beside french lake' is the wordplay.
'one italian' becomes 'una' (I can't explain this - if you can you should believe this answer much more).
'beside' means one lot of letters go next to another (I've seen this in other clues).
'french lake' becomes 'lac' ('lake' in French).
'una' put after 'lac' is 'LACUNA'.
'found by' acts as a link.
Can you help me to learn more?
(Other definitions for lacuna that I've seen before include "A gap, maybe in a book" , "Gap or hiatus" , "Blank gap or missing part" , "Hiatus - cavity" , "something missing" .)