- a deceptive, misleading, or false notion, belief, etc.: That the world is flat was at one time a popular fallacy.
- a misleading or unsound argument.
- deceptive, misleading, or false nature; erroneousness.
- Logic. any of various types of erroneous reasoning that render arguments logically unsound.
- Obsolete. deception.
Origin of fallacy
SynonymsSee more synonyms for fallacy on Thesaurus.com
Examples from the Web for fallacy
In fact, what this map really showed was the fallacy of aggregates – and how statistics can mask real cultural shifts.Beer Countries vs. Wine Countries
December 7, 2014
Every time the thermometer drops, another anti-science politician mocks climate change as a fallacy.From Snowy Atlanta to Sunny Sochi, It's All About Global Weirding
February 12, 2014
To prove the fallacy of said cargo cult, Olson goes into the numbers.The GOP's Socially Conservative Minority Voter Cargo Cult
December 15, 2012
The many who believe that human knowledge begins in the academy are guilty of the fallacy of “lecturing birds on how to fly.”A Manifesto for Disorder: Nassim Nicholas Taleb’s ‘Antifragile’ Reviewed
November 26, 2012
Which brings me to the real point here: the entire premise of Mr. Rubin's moral question is built upon a fallacy.A Sophistic Moral Case For War
October 27, 2012
His want of success arose from the insufficiency, not the fallacy, of theory.Tales And Novels, Volume 8 (of 10)
Do not commit the fallacy of sitting down for a little rest.The Forest
Stewart Edward White
There is no need of a long explanation to show the fallacy of this idea.The Sexual Question
Godwin, in all this, reproduces the current fallacy of his generation.Shelley, Godwin and Their Circle
H. N. Brailsford
A few minutes served to convince her of the fallacy of this expectation.Chronicles of Border Warfare
Alexander Scott Withers
- an incorrect or misleading notion or opinion based on inaccurate facts or invalid reasoning
- unsound or invalid reasoning
- the tendency to mislead
- logic an error in reasoning that renders an argument logically invalid
Word Origin and History for fallacy
late 15c., "deception, false statement," from Latin fallacia "deception," noun of quality from fallax (genitive fallacis) "deceptive," from fallere "deceive" (see fail (v.)). Specific sense in logic dates from 1550s. An earlier form was fallace (c.1300), from Old French fallace.
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.)