non-gradable vs propitious

non-gradable

adj
  • (of an adjective) Describing a quality that cannot normally be varied because it is extreme (e.g. freezing), absolute (e.g. dead), or classification (e.g. nuclear). 

  • That cannot be graded. 

noun
  • Any adjective that is not gradable. 

propitious

adj
  • Advantageous. 

  • Favorable; benevolent. 

  • Characteristic of a good omen. 

How often have the words non-gradable and propitious occurred in a corpus of books? (source: Google Ngram Viewer )