Okay kiddo, so imagine you have two friends - one of them, let's call her Sarah, is really nice to you and always says what she wants. If she doesn't like something, she tells you straight up. The other friend, let's call him Jack, is a bit different. Jack also doesn't like things sometimes but he doesn't tell you directly. Instead, he says something that seems nice but actually means something else. That's called being passive-aggressive.
For example, if Jack doesn't want to play with you, he might say, "Oh, I'm too tired to play right now. Maybe later." But really, he doesn't want to play at all. Or if you ask Jack if he wants a cookie and he says, "No, thanks. I'm watching my figure." Even though he really wants a cookie, he's being passive-aggressive by not saying what he really wants.
Sometimes, people act passive-aggressive when they're feeling upset or angry, but they don't want to say it directly. It's like they're trying to get back at you in a sneaky way by saying things that sound nice but actually mean something else. It can be confusing and frustrating to deal with, but it's important to remember that it's not a nice way to behave towards others.
So, if you come across someone who is being passive-aggressive, it's important to talk to them and try to understand why they're acting that way. It might be that they're upset about something you did or said and don't know how to express it, or they might need some help expressing their feelings in a more direct way. Either way, it's important to be kind and patient with them, but also firm in telling them that their behavior is not okay.