Okay kiddo, imagine you have a secret hiding place in your room where you keep all your favorite toys. You don't want anyone to find out about it, right? That's what tamper-resistant means – making something so that nobody can mess with it or find out your secrets.
Now let's say you decide to put a lock on your secret hiding place so nobody can open it without the key. That makes it tamper-resistant because it's hard for anyone to get inside without your permission.
In the grown-up world, tamper-resistant can mean lots of different things. For example, companies might make medicine bottles that are tamper-resistant so nobody can open them and put something dangerous inside. Or they might make computer chips that are tamper-resistant so nobody can steal information from them.
Basically, tamper-resistant means making something really hard to mess with or break into, so that people's secrets and safety are protected.