Unthinkable

Unthinkable means something that is very hard to even imagine or think about. Imagine you have a favorite toy that you love to play with all the time. Now, imagine someone taking that toy away from you and never giving it back. That would be unthinkable, right? It's hard to even picture that happening because it's so sad and scary. So, when people say something is unthinkable, it means it's something that they can't even imagine or think about because it's really bad or scary.