/ Dictionary / Index F fallacy: Meaning and Definition of Find definitions for: fal•la•cy Pronunciation: (fal'u-sē), [key] — pl. -cies. 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. any of various types of erroneous reasoning that render arguments logically unsound. deception. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: fallacy (Thesaurus) fallacious fallal Related Content Daily Word Quiz: cautious Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language