antediluvial vs atavistic

antediluvial

adj
  • Antiquated. 

  • Of or pertaining to a time before Noah's flood. 

atavistic

adj
  • Of a throwback or exhibiting primitivism. 

  • Relating to earlier, more primitive behavior that returns after an absence. 

  • Of the recurrence of a trait reappearing after an absence of one or more generations due to a chance recombination of genes. 

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