pest          
noun [ C ] uk/pest/ us/pest/
 (破坏庄稼的)有害小动物(或昆虫);害虫
an insect or small animal that is harmful or damages crops
  common pests such as rats, mice, or cockroaches 老鼠、蟑螂等常见害虫 
  informal讨厌的人;(尤指孩子)讨厌鬼 
an annoying person, especially a child
  Put that back, you little pest! 把它放回去,你这个小讨厌鬼!