pest vs reassurance

pest

noun
  • Any destructive insect that attacks crops or livestock; an agricultural pest. 

  • An animal regarded as a nuisance, destructive, or a parasite, vermin. 

  • An annoying person, a nuisance. 

  • An invasive weed. 

reassurance

noun
  • The act of confirming someone's opinion or impression. 

  • Reinsurance. 

  • The feeling of being reassured, of having confidence restored, of having apprehensions dispelled. 

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