pest

noun

1. 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

   Synonyms pestilence pestis plague

   Source: WordNet 3.0

2. any epidemic disease with a high death rate

   noun.state

   Synonyms pestilence plague

   Source: WordNet 3.0

3. a persistently annoying person

   noun.person

   Synonyms blighter cuss gadfly pesterer

   Source: WordNet 3.0

4. any unwanted and destructive insect or other animal that attacks food or crops or livestock etc.

   noun.animal

   Examples

   He sprayed the garden to get rid of pests.

   Many pests have developed resistance to the common pesticides.

   Source: WordNet 3.0

5. A fatal epidemic disease; a pestilence; specif., the plague.

   noun

   Source: webster1913