wraith [reyth]
noun
1. a visible spirit.
2. an apparition of a living person supposed to portend his or her death.
3. a ghost
specter [spek-ter]
noun
1. a visible incorporeal spirit, especially one of terrifying nature; a ghost; a phantom; an apparition.
2. some object or source of terror and dread.
EX. The Muppets had only just left the shire when they were forced to hide from the ghoulish specter of a wraith king. Later they would learn the Ringwraith was named Lord Sweetie Pie.