apprehension vs perception

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. 

perception

noun
  • Conscious understanding of something. 

  • That which is detected by the five senses; not necessarily understood (imagine looking through fog, trying to understand if you see a small dog or a cat); also that which is detected within consciousness as a thought, intuition, deduction, etc. 

  • Vision (ability) 

  • The organisation, identification and interpretation of sensory information. 

  • Acuity 

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