frustrate vs ward off

frustrate

verb
  • To hinder or thwart. 

  • To cause stress or annoyance. 

  • To disappoint or defeat; to vex by depriving of something expected or desired. 

adj
  • ineffectual; useless; fruitless. 

ward off

verb
  • To avert or prevent. 

  • To parry, or turn aside. 

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