Synonyms for Pest (same or very similar meaning)
WordNet sense 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):
pestilence, plague, pestis
WordNet sense 2 (a persistently annoying person):
cuss, gadfly, blighter, pesterer
From the ODE community, based on WordNet
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