fatally vs harmfully

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. 

harmfully

adv
  • In a harmful manner. 

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