noun (n)

• 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(noun.state)

  Synonym:
  pestilence, pestis, plague
  

  source: wordnet30
• any epidemic disease with a high death rate(noun.state)

  Synonym:
  pestilence, plague
  

  source: wordnet30
• a persistently annoying person(noun.person)

  Synonym:
  blighter, cuss, gadfly, pesterer
  

  source: wordnet30
• any unwanted and destructive insect or other animal that attacks food or crops or livestock etc.(noun.animal)

  Example:
  He sprayed the garden to get rid of pests.
  Many pests have developed resistance to the common pesticides.
  

  source: wordnet30
• A fatal epidemic disease; a pestilence; specif., the plague.(noun)

  source: webster1913