fourth estate vs thumbsucker

fourth estate

noun
  • Journalism or journalists considered as a group; the press. 

thumbsucker

noun
  • A piece of serious journalism that explains the background of current events and interprets them in a manner comforting to the intended readers. 

  • Someone who sucks their thumb. 

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