spectre

Noun

• a mental representation of some haunting experience
  • he looked like he had seen a ghost
    
  • it aroused specters from his past
    

• a ghostly appearing figure
  • we were unprepared for the apparition that confronted us
    

Related words

• Synonyms: 
  ghost , shade , spook , wraith , specter , apparition , phantom , phantasm , phantasma , fantasm