Okay kiddo, so you know how we have rules in our society to make sure everyone lives together peacefully? Well, sometimes people break those rules and do bad things. When someone breaks the rules, it's up to the police and the courts to figure out what happened and give them a fair punishment.
Now imagine if someone tried to trick the police or the courts into thinking the person who broke the rules didn't really do it, even though they did. That's what we call "perverting the course of justice." It's like if someone is trying to hide the truth and mislead the people who are supposed to find out what really happened.
For example, let's say your friend was caught stealing a toy from a store. If you lied to the police and said you saw someone else take it or that your friend didn't take it, that would be perverting the course of justice. You would be trying to cover up what really happened and protect your friend from getting in trouble for what they did.
It's important to always tell the truth and not try to trick the people who are supposed to figure out what happened when someone breaks the rules. That's because if people can't trust that the police or the courts will find out the truth, then our whole society won't work properly and there will be chaos.