Why is a terrible doctor called a “quack”?

Many people will go to a check up with their doctor and come back n’ say “wow my doctor is such quack”. Because he seems incompetent, or just says nonsense. Well basically that’s where the word originated from..nonsense. It comes from the old days, when dubious medicine men traveled from town to town and sold their amazing healing aliments and ointments. The Quack comes from the Quack of a duck which is repeatedly nonsensical just like the dubious medicine man’s words.

Did you know that only the female dabbling duck is the only duck that quack’s and not any other duck of any other family? It was also always thought that a duck’s quack don’t echo but the myth has been since debunked by many sources, universities and even the famous tv show Mythbusters.