gnat vs pest

gnat

noun
  • An annoying person. 

  • Any small insect of the order Diptera, specifically within the suborder Nematocera. 

pest

noun
  • An annoying person, a nuisance. 

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

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

  • An invasive weed. 

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