Atone means to make amends for a sin, a crime = to make up for something - say if you broke someone's window, you may be atoned (by them and in the act of doing) by replacing the window.
Unatoned sins - means sins which you've not paid for yet.
Crisp breeze = means feeling a bit sharp....... crisp is - you know what dead tree leaves feel like? They're dry, and they break in your hands easily - on a cold morning, the air can be crisp - it means sharp like -
Vision can be crisp too, say the TV screen was dirty, but then you cleaned it, the images would then look crisp.
Atone - atonement are words - UNatoned is just "not being atoned" forgiven/made amends for etc