Try Our Apps


World Series Quiz


[fuh-ley-shuh s] /fəˈleɪ ʃəs/
containing a fallacy; logically unsound:
fallacious arguments.
deceptive; misleading:
fallacious testimony.
disappointing; delusive:
a fallacious peace.
Origin of fallacious
1500-10; < Latin fallāciōsus deceitful, deceptive. See fallacy, -ous
Related forms
fallaciously, adverb
fallaciousness, noun
nonfallacious, adjective
nonfallaciously, adverb
nonfallaciousness, noun
unfallacious, adjective
unfallaciously, adverb Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2016.
Cite This Source
Examples from the Web for fallacious
Contemporary Examples
Historical Examples
  • Got in light and fallacious ways, the money dwindles; only when gathered by labour does it really increase.

  • No compromise for him, no evasions, no fallacious, unsecured promises to pay.

    Dream Days Kenneth Grahame
  • The fallacious assumption implied in the query, quid Christianis cum regibus?

    The Cradle of Mankind W.A. Wigram
  • Still, through this fallacious medium, a real enlargement of ideas is attained.

    The Republic Plato
  • The very greatest care is necessary to determine what facts are true and what are fallacious.

    Expository Writing Mervin James Curl
  • Only what must be avoided are fallacious inferences, my dear Lena—especially at this hour.

    Victory Joseph Conrad
  • What became of his fallacious hope of waiting when events were driving on at this rate?

    That Fortune Charles Dudley Warner
  • There has never been a religion too gross, too fallacious, to fail of followers.

    The Tyranny of the Dark Hamlin Garland
  • Subsequently another company was formed in New York, being influenced by a fallacious view of the silicious sand.

British Dictionary definitions for fallacious


containing or involving a fallacy; illogical; erroneous
tending to mislead
delusive or disappointing: a fallacious hope
Derived Forms
fallaciously, adverb
fallaciousness, noun
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for fallacious

c.1500, from fallacy (Latin fallacia) + -ous. Related: Fallaciously; fallaciousness.

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source

Word of the Day

Difficulty index for fallacious

Some English speakers likely know this word

Word Value for fallacious

Scrabble Words With Friends

Nearby words for fallacious