It will come as no surprise that fallacious is related to the noun fallacy, meaning “delusion” or “falsehood.” Both words come from the Latin word fallacia, which in turn comes from fallere, meaning …

FALLACIOUS definition: containing a fallacy; logically unsound. See examples of fallacious used in a sentence.

The most common fallacious argument is that current climate change must be natural because climate has changed naturally in the past.

Definition of fallacious adjective in Oxford Advanced Learner's Dictionary. Meaning, pronunciation, picture, example sentences, grammar, usage notes, synonyms and more.

1. Containing or based on a fallacy: a fallacious assumption. 2. Tending to mislead; deceptive: fallacious testimony.

fallacious, adj. meanings, etymology, pronunciation and more in the Oxford English Dictionary

5 days ago · Adjective fallacious (comparative more fallacious, superlative most fallacious) Characterized by fallacy; false or mistaken. Synonyms: erroneous, incorrect, wrong; see also …

If an idea, argument, or reason is fallacious, it is wrong because it is based on a fallacy.

Sep 18, 2025 · First off, let’s clarify what “fallacious” actually means. The word describes something that is misleading or deceptive because it appears to be logical or valid but isn’t really. Essentially, a …

Britannica Dictionary definition of FALLACIOUS [more fallacious; most fallacious] formal : containing a mistake : not true or accurate a fallacious [= false] set of assumptions fallacious [= misleading] …