circumambient vs impending

circumambient

adj
  • Surrounding. 

  • Including all aspects of; encompassing. 

adv
  • in a circumambient manner 

impending

adj
  • Approaching; drawing near; about to happen or expected to happen. 

noun
  • Something that impends or threatens; an expected event. 

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