defunct

Something described as defunct is no longer in use or no longer functioning. It was active once, but now it has stopped for good. Think of an old factory that's closed down, a website nobody uses anymore, or a law that's no longer in force. It used to work, but now it doesn't.

The word has a slightly formal feel and often implies something was once important or useful. You wouldn't say your favorite pen is defunct if it runs out of ink—you'd just say it's empty. But you might describe a discontinued product line or a closed hospital as "defunct." The word often fits best for things that have finished their role.

The word "defunct" describes something that is no longer in effect or use; it is inactive, obsolete, or has ceased to exist. It carries a sense of finality—it's not just temporarily out of service, but permanently ended. For example: "The once-popular video rental store became defunct with the rise of streaming services."

Defunct isn't limited to physical objects. It can also describe organizations, laws, or ideas that are no longer relevant. "The treaty is now defunct" means it's no longer legally binding. A defunct political party is one that has lost its power, members, and influence entirely.

While often used for things that have simply fallen out of use due to progress (like a rotary phone being considered defunct in the age of smartphones), it can also imply failure or abandonment. A defunct project is one that was started but has been permanently shelved or forgotten.

Something can be defunct even when it still exists in form. An old school building may still stand, or an old law may still be in archives, but both are no longer serving their purpose. In almost all cases, when something is described as defunct, it is considered permanently out of commission.

So, whether you're talking about a forgotten technology, an abandoned business, or a retired law, "defunct" signals that something has reached the end of its useful life and is no longer functioning as intended.