Superquick means very fast! It's like when you run really, really, really fast or when someone does something really quickly. For example, you might say that a superhero is superquick because they can move faster than anyone else! Or you might say that a cheetah is superquick because it can run really fast.
Sometimes people use the word superquick to talk about something that happens really fast, like if you need to finish your homework superquick because you want to go play outside. It's like a special way of saying "really fast" that makes it sound even more impressive!