The word quack is taken from the Middle English word quek. Quack has an imitative origin. It is a characteristic sound made by a duck. A duck quacks. Here, quack is used as a verb. When someone makes this sound of a duck, he said to be quacking. Something that produces this sound is referred to as quacky.
Quack is a short word for quacksalver. A person who presents himself to be a doctor or physician, although he is not is termed a quack. Such a person even treats people and offers medical advice. Anything that relates to or is characteristic of quack is also referred to as a quack. For example: a quack medicine or quack cure. When someone acts as a quack, he is supposed to be quacking.
Quack is a short word for quacksalver. A person who presents himself to be a doctor or physician, although he is not is termed a quack. Such a person even treats people and offers medical advice. Anything that relates to or is characteristic of quack is also referred to as a quack. For example: a quack medicine or quack cure. When someone acts as a quack, he is supposed to be quacking.