a pernicious and malign influence that is hard to get rid of; "racism is a pestilence at the heart of the nation"; "according to him, I was the canker in their midst"
an object of dread or apprehension; "Germany was always a bugbear for France"; "A foolish consistency is the hobgoblin of little minds"--Ralph Waldo Emerson
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"; "many pests have developed resistance to the common pesticides"