pest

Noun

• 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
    

• a persistently annoying person

• any epidemic disease with a high death rate

• 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

Related words

• Synonyms: 
  blighter , cuss , pesterer , gadfly , plague , pestilence , pestis