fallacy

[fal-uh-see]

noun

plural

fallacies 

1. a deceptive, misleading, or false notion, belief, etc..

   That the world is flat was at one time a popular fallacy.

   Synonyms: misapprehension, delusion, misconception

2. a misleading or unsound argument.

3. deceptive, misleading, or false nature; erroneousness.

4. Logic.,  any of various types of erroneous reasoning that render arguments logically unsound.

5. Obsolete.,  deception.

fallacy

/ ˈfæləsɪ /

noun

1. an incorrect or misleading notion or opinion based on inaccurate facts or invalid reasoning

2. unsound or invalid reasoning

3. the tendency to mislead

4. logic an error in reasoning that renders an argument logically invalid

fallacy

1. 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.)

Word History and Origins

Origin of fallacy¹

First recorded in 1350–1400; from Latin fallācia “a trick, deceit,” from fallāc- (stem of fallāx ) “deceitful” + -ia -y ³; replacing Middle English fallace, from Middle French

Word History and Origins

Origin of fallacy¹

C15: from Latin fallācia , from fallax deceitful, from fallere to deceive

Example Sentences

In such a predicament, many would fall prey to a mixed-up way of thinking called the “sunk cost fallacy,” which is best explained by telling a brief story.

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That would be a fallacy, but Mr. Bottum didn’t commit it.

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“There’s this fallacy that companies were lowering the bar,” she says.

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On wages, Mr. Vance is repeating the lump of labor fallacy that American and foreign workers compete for a limited number of jobs.

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I place that term in quotation marks since, as many people have said and continue to say, the version of “debate” that Kirk popularized is a wrestling match in a mud pit of logical fallacies.

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Related Words

• deception 
• falsehood 
• heresy 
• inconsistency 
• misinterpretation www.thesaurus.com
• paradox 
• untruth