foreboding vs prior knowledge

foreboding

noun
  • An evil omen. 

  • A sense of evil to come. 

adj
  • Of ominous significance; serving as an ill omen; foretelling of harm or difficulty. 

prior knowledge

noun
  • Used other than figuratively or idiomatically: see prior, knowledge. 

  • Knowledge of a set of circumstances sufficient to make actions based on those circumstances wrongful. 

  • Prior to the inception of an insurance policy, knowledge of specific extant circumstances that could reasonably give rise to a claim under that policy. 

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