pest ‎(plural pests). ( 1 originally) A plague, pestilence, epidemic. 2  An annoying, harmful, often destructive creature. 3  An annoying person.( 4 Britain, slang) Someone with poor social discipline who continually bothers uninterested women.est ‎(plural pests). ( 1 originally) A plague, pestilence, epidemic. 2  An annoying, harmful, often destructive creature. 3  An annoying person.