Derelict describes something abandoned and falling apart. A derelict building might have broken windows, crumbling walls, and vines growing through the roof because no one has taken care of it for years. Ships left to rot in harbors become derelict, their paint peeling and their decks warped by weather.

The word carries a sense of sad neglect. Something derelict was once useful or valuable but has been forgotten or left behind. An old factory, a rusted car, or a neighborhood playground with broken swings could all be described as derelict. These places feel lonely because they show what happens when people stop maintaining things that were once important.

When describing a person, derelict means failing completely at your responsibilities. A derelict parent abandons their children instead of caring for them. A ship captain would be derelict in his duty if he abandoned his vessel during a storm. In this sense, it's a serious accusation suggesting someone has given up on obligations they should never ignore.