gnat vs vermin

gnat

noun
  • An annoying person. 

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

vermin

noun
  • Obnoxious, or mean and offensive person or people. 

  • Any one of various common types of small insects or animals which cause harm and annoyance. 

  • Animals that prey on game, such as foxes or weasels. 

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