What does it mean to be innocent? I am asking, because the word is used so much in US and UK both, but in DK it is almost exclusively used in connection with legal matters so I have no real idea of the concept apart from that.

Examples, 'innocent bystander' we would call 'bystander', 'innocent civilians' would be 'civilians', 'saving innnocent lives' would be 'saving lives'.

What is the opposite of 'innocent', when it is not 'guilty'?

Thoughts and comments appreciated.