Okay, so you know how when you do something wrong, like taking a cookie you're not supposed to or hitting your friend, your parents might make you say sorry and promise never to do it again?
Well, sometimes grown-ups do really big no-no's and go to jail for it. When they finish their time in jail, they might still have to promise to behave really well and follow a lot of rules. This is called probation.
Now, sometimes grown-ups do things that are so bad that they have to promise to be extra-super good for the rest of their lives. This is called lifetime probation.
It's kind of like having a really strict babysitter who makes sure you never do anything wrong again. They might tell you where you can go, who you can talk to, and even what kind of job you can have. If you break any of these rules, you might have to go back to jail.
It might sound tough, but it's because the grown-up did something really serious and they need to make sure they don't hurt anyone again.