pest vs problem

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. 

problem

noun
  • A puzzling circumstance. 

  • A difficulty that has to be resolved or dealt with. 

  • A set of moves required to complete a climb. 

  • A question to be answered, schoolwork exercise. 

  • Objection. 

  • Difficulty in accepting or understanding or refusal to accept or understand. 

adj
  • Causing a problem; problematic; troublesome. 

  • Difficult to train or guide; unruly. 

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