contortionist vs tightrope walker

contortionist

noun
  • An acrobat who is capable of twisting his or her body into unusual positions. 

  • One who twists words and phrases. 

tightrope walker

noun
  • An acrobat who practices tightrope walking. 

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