Defunct means no longer existing, operating, or functioning. When something is defunct, it has stopped working or ceased to exist, usually permanently.

A defunct company is one that has gone out of business and closed its doors for good. The factories are empty, the workers have found other jobs, and the products are no longer made. You might read about a defunct railroad line that once carried passengers between cities but stopped running decades ago, its tracks now overgrown with weeds.

Organizations, traditions, and even laws can become defunct. A school club that ran out of members and dissolved is now defunct. An old law that nobody enforces anymore might be considered defunct, even if it's technically still on the books.

The word carries a sense of finality. Something defunct isn't just temporarily closed or paused: it's finished. When historians study defunct civilizations like ancient Rome or the Maya, they're examining societies that no longer exist in their original form.

You might see defunct used in phrases like “the now-defunct magazine” or “a defunct technology,” describing things that once thrived but have since disappeared into history.