Bluejacking is a way to send messages or pictures from one phone to another phone using Bluetooth. Bluetooth is a way for phones to talk to each other without using wires or the internet.
Imagine you have a toy car and your friend has a toy car, too. You can make your car talk to your friend's car using a special toy car language. This is like how phones can talk to each other using Bluetooth.
Now imagine you have a magic toy car that lets you send secret messages to your friend's toy car. Bluejacking is like that magic toy car. You can use it to send secret messages or pictures to other phones without the people knowing who sent it.
But don't worry, bluejacking is just for fun and games with your friends. It can't hurt your phone or make it do anything bad.