adumbration vs prefiguration

adumbration

noun
  • A rough or symbolic representation; a vague indication of what is to come, a foreshadowing. 

  • The state of being in shadow or shade; (countable) a shadow. 

  • The outline of a charge (“image displayed on an escutcheon”), sometimes filled in with a darker shade than the field. 

  • The form of an object as seen by an observer. 

  • A faint sketch; a brief representation, an outline. 

prefiguration

noun
  • A vague representation or suggestion of something before it has happened or been accomplished. 

  • Something that prefigures. 

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