lowbrow vs thick as a brick

lowbrow

adj
  • Unsophisticated, not intended for an audience of intelligence, education or culture. 

noun
  • Someone or something of low education or culture. 

  • An underground populist visual art movement that arose in the Los Angeles area in the late 1960s, inspired by comics, punk music, graffiti, etc. 

thick as a brick

adj
  • Very stupid; slow to learn or understand. 

How often have the words lowbrow and thick as a brick occurred in a corpus of books? (source: Google Ngram Viewer )