haunted vs spectral

haunted

adj
  • Of a location, frequented by a ghost or ghosts. 

  • Showing a feeling of being disturbed. 

  • Obsessed (by an idea, threat, etc.). 

spectral

adj
  • Of, or pertaining to, spectres; ghostly. 

  • Of, or pertaining to, spectra; classified according to frequency or wavelength (of light etc) 

How often have the words haunted and spectral occurred in a corpus of books? (source: Google Ngram Viewer )