A straw man is a common form of argument and is an informal fallacy based on giving the impression of refuting an opponent's argument, while actually refuting an argument that was not advanced by that opponent.

The so-called typical "attacking a straw man" argument creates the illusion of having completely refuted or defeated an opponent's proposition by covertly replacing it with a different proposition (i.e. "stand up a straw man") and then to refute or defeat that false argument ("knock down a straw man") instead of the original proposition.