ghoulish vs spectral

ghoulish

adj
  • Of or pertaining to corpses and graverobbing. 

  • Of or pertaining to ghouls. 

  • Fascinated by corpses. 

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 ghoulish and spectral occurred in a corpus of books? (source: Google Ngram Viewer )