clarity vs coherence

clarity

noun
  • The state or measure of being clear, either in appearance, thought or style; lucidity. 

  • The ability to be easily understood. 

coherence

noun
  • The quality of cohering, or being coherent; internal consistency. 

  • The property of having the same wavelength and phase. 

  • A logical arrangement of parts, as in writing. 

  • A semantic relationship between different parts of the same text. 

  • The quality of forming a unified whole. 

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