- The definition of a fallacy is a deceptive or false notion.
An example of fallacy is the idea that the sun spins around the earth.
- Obsolete deception
- aptness to mislead; deceptive or delusive quality: the fallacy of the senses
- a false or mistaken idea, opinion, etc.; error
- an error in reasoning; flaw or defect in argument
- Logic an argument which does not conform to the rules of logic, esp. one that appears to be sound
Origin: Middle English fallace ; from Old French ; from Classical Latin fallacia, deception, artifice ; from fallax (gen. fallacis), deceitful ; from fallere, to deceive: see fail
Used by arrangement with John Wiley & Sons, Inc.
noun pl. fal·la·cies
- A false notion.
- A statement or an argument based on a false or invalid inference.
- Incorrectness of reasoning or belief; erroneousness.
- The quality of being deceptive.
Origin: Alteration of Middle English fallace, from Old French, from Latin fallācia, deceit, from fallāx, fallāc-, deceitful, from fallere, to deceive.
fallacy - Cultural Definition
A false or mistaken idea based on faulty knowledge or reasoning. For example, kings who have divorced their wives for failing to produce a son have held to the fallacy that a mother determines the sex of a child, when actually the father does. (See sex chromosomes.)