reassuring vs spectral

reassuring

noun
  • reassurance 

adj
  • That reassures; causing comfort or confidence. 

spectral

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

  • Of, or pertaining to, spectres; ghostly. 

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