pest in WordNet English dictionary

1. a persistently annoying person
   pest  blighter  cuss  pesterer  gadfly 
   
2. any unwanted and destructive insect or other animal that attacks food or crops or livestock etc.
   "he sprayed the garden to get rid of pests"; "many pests have developed resistance to the common pesticides"
   pest 
   
3. any epidemic disease with a high death rate
   plague  pestilence  pest 
   
4. a serious (sometimes fatal) infection of rodents caused by Yersinia pestis and accidentally transmitted to humans by the bite of a flea that has bitten an infected animal
   plague  pestilence  pest  pestis