leggerezza... "lightness, nimbleness". "ezza" is a suffix used to create abstract nouns in Italian. So in this case it turns the adjective "leggiero" into a noun, "leggerezza". Evidently the "i" in your spelling is an error; my dictionary (Mondadori's) drops the "i" in "leggierro" in "leggerezza". I think it's spelled your way in the sheet music, though....
Logged
= o o = \ ' / "You're as good as the the best work you've done"