the fact of being not guilty of a crime [≠ guilt]:
Can you prove your innocence?
protest/maintain your innocence (=say repeatedly that you are not guilty)
The prisoners continued to protest their innocence.
lack of experience of life or knowledge of the bad things in the world:
In our innocence we believed everything we were told.
the innocence of childhood
if you do or say something in all innocence, you have no intention of doing harm or of offending anyone