To wreck something means to completely destroy or ruin it.

If a ship is wrecked, it is damaged so much that it sinks or can no longer sail.

A wreck is something such as a ship, car, plane, or building which has been destroyed, usually in an accident.

A wreck is an accident in which a moving vehicle hits something and is damaged or destroyed.

If you say that someone is a wreck, you mean that they are very exhausted or unhealthy.