mordacious vs vitriolic

mordacious

adj
  • Sharp in intent, sarcastic 

  • Prone to biting, aggressive (of an animal etc.). 

  • Biting, causing a physical bite or sting; corrosive 

  • sharp or caustic in style or tone. 

vitriolic

adj
  • Bitterly scathing, caustic. 

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