pest pest /ˈpɛst/

noun

1. Any unwanted and destructive insect or other animal that attacks food or crops or livestock etc.  ( pest )
   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
   he sprayed the garden to get rid of pests
    Many pests have developed resistance to the common pesticides
   many pests have developed resistance to the common pesticides
   
   
2. A persistently annoying person  ( blighter [Informal, British] , pest , pesterer , cuss [Informal] , gadfly )
   a persistently annoying person
   
3. Any epidemic disease with a high death rate  ( pest , pestilence , plague )
   any epidemic disease with a high death rate
   
   
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  ( pest , pestilence , pestis , plague )
   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