non-gradable vs usual

non-gradable

noun
  • Any adjective that is not gradable. 

adj
  • That cannot be graded. 

  • (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). 

usual

noun
  • A specific good or service (e.g. a drink) that someone typically orders. 

  • The typical state of something, or something that is typical. 

adj
  • Most commonly occurring; typical. 

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