Dysfunctional describes something that doesn't work the way it should. If you know all the printers at the school computer lab are dysfunctional, it's better to print your book report at home.
Dys- means "bad," and function means "proper purpose," so when something's working badly, it's dysfunctional. For example, your toaster that always burns the toast is dysfunctional. The word dysfunctional is often used to describe relationships or even whole families whose ways of relating to one another are mentally harmful or are so complicated that nothing feels easy or natural about them.