fatally vs lethally

fatally

adv
  • In a fatal manner; lethally. 

  • Ultimately, with finality or irrevocability, moving towards the demise of something. 

  • Fatedly; according to the dictates of fate or doom. 

lethally

adv
  • In a lethal manner, in manner which is or will be fatal. 

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