one who exposes or ridicules the falseness, sham, or exaggerated claims of another
One can readily see that debunk is constructed from the prefix de-, meaning “to remove,” and the word, ‘bunk’, but what is the origin of the word, ‘bunk’, denoting the nonsense that is to be removed? ‘Bunk’ came from a place where much bunk has originated, the United States Congress. During the 16th Congress (1819-1821) Felix Walker, a representative from western North Carolina whose district included Buncombe County, carried on with a dull speech in the face of protests by his colleagues. Walker later explained he had felt obligated “to make a speech for Buncombe.” Such a masterful symbol for empty talk could not be ignored by the speakers of the language, and Buncombe, spelled Bunkum in its first recorded appearance in 1828 and later shortened to bunk, became synonymous with claptrap. The response to all this bunk seems to have been delayed, for debunk is not recorded until 1923.