brutally vs unrelentingly

brutally

adv
  • In a brutal manner; viciously, barbarically. 

  • Extremely. 

  • In a direct way that does not attempt to hide, disguise or mask unpleasantness; directly. 

unrelentingly

adv
  • In an unrelenting manner; rigidly; cruelly. 

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