apprehension vs know

apprehension

noun
  • Perception; the act of understanding using one's intellect without affirming, denying, or passing any judgment 

  • Opinion; conception; sentiment; idea. 

  • Anticipation, especially of unfavorable things such as dread or fear or the prospect of something unpleasant in the future. 

  • The faculty by which ideas are conceived or by which perceptions are grasped; understanding. 

  • The physical act of seizing or taking hold of (something); seizing. 

  • The act of seizing or taking by legal process; arrest. 

know

noun
  • Knowledge; the state of knowing. 

  • Knowledge; the state of knowing; now confined to the fixed phrase ‘in the know’ 

verb
  • To perceive the truth or factuality of; to be certain of or that. 

  • To experience. 

  • To understand or have a grasp of through experience or study. 

  • To be or become aware or cognizant. 

  • To be able to play or perform (a song or other piece of music). 

  • To be acquainted or familiar with; to have encountered. 

  • To be aware of; to be cognizant of. 

  • To recognize as the same (as someone or something previously encountered) after an absence or change. 

  • To have knowledge; to have information, be informed. 

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