illusion vs understanding

illusion

noun
  • The state of being deceived or misled. 

  • A misapprehension; a belief in something that is in fact not true. 

  • Anything that seems to be something that it is not. 

  • A magician’s trick. 

understanding

noun
  • The act of one that understands or comprehends; comprehension; knowledge; discernment. 

  • Opinion, judgement or outlook. 

  • An informal contract; mutual agreement. 

  • A reconciliation of differences. 

  • Sympathy. 

  • Reason or intelligence, ability to grasp the full meaning of knowledge, ability to infer. 

adj
  • Showing compassion, tolerance, and forbearance. 

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