What exactly does getting immunity mean?

Question

The Olsen girl and the mother in Florida whose little girl is missing......If they are granted immunity what does it mean? The mom could never go to jail? Even if they found the little girls body? And the mom had something to do with it? Why does she need immunity if she really doesn't know what happened?

Answer 1

It means that you can't be prosecuted for the crime in question.

Answer 2

it means they won't prosecute.

Answer 3

Getting off scott free after grassing up your mates...

Answer 4

It means that you can't ever be prosecuted for your part in the crime.