privative vs unpropitious

privative

adj
  • consisting in the absence of something; negative 

  • causing privation; depriving 

  • indicating the absence of something 

noun
  • something that causes privation or indicates an absence 

unpropitious

adj
  • not propitious; unfavourable, untimely 

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