clear as a bell vs prominent

clear as a bell

adj
  • Totally clear; distinct and unmistakeable, as a bell's tone is clearly heard. 

prominent

noun
  • Any of various moths having a conspicuous projection on the inner margin of the wings. 

  • In Nazi concentration camps, an inmate entrusted with minor supervisory duties and rewarded with perquisites. 

adj
  • standing out, or projecting; jutting; protuberant 

  • likely to attract attention from its size or position; conspicuous 

  • eminent; distinguished above others 

How often have the words clear as a bell and prominent occurred in a corpus of books? (source: Google Ngram Viewer )