Usui, cornered, needles Aoi of her immatureness of not actually knowing the meaning of what she's doing.    From Wordnik.com.  [Anime Nano!] Reference

Today we get another issue about a bug which could not detect a leap year (what immatureness by Microsoft).    From Wordnik.com.  [Megite Technology News: What's Happening Right Now] Reference

It is true that for a few years after leaving the cradle he had exhibited a certain immatureness, but as soon as he put on knickerbockers and began to go about a little he outgrew all that.    From Wordnik.com.  [Uneasy Money] Reference

Covent Garden, the child stepping blithely by my side, graceful even then, notwithstanding her immatureness, and quaintly attractive, though her deep blue eyes were full of tears, and the white terror had not passed wholly from her face.    From Wordnik.com.  [The Master Mummer] Reference