sophism

A plausible but fallacious argument.

Deceptive or fallacious argumentation.

A false argumentation devised for the exercise of one's ingenuity or for the purpose of deceit; sometimes, a logically false argumentation; a fallacy.

Syn. A sophism is an argument known to be unsound by him who uses it; a paralogism is an unsound argument used without knowledge of its unsoundness. Paralogism is a strictly technical word of logic; sophism is not. Sophistry applies to reasoning as sophism to a single argument. See fallacy.

The doctrine or mode of reasoning practiced by a sophist; hence, any fallacy designed to deceive.