beetling vs protuberant

beetling

adj
  • Jutting or protruding, especially of a person's brows. 

noun
  • The process by which fabrics, etc. are beetled, or beaten with a mallet. 

protuberant

adj
  • Swelling or bulging outward. 

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