Meaning: A mistaken belief, especially one based on unsound argument. A failure in reasoning that renders an argument invalid.
Synonyms: Misconception, misbelieve, delusion, mistaken impression, error, misapprehension, misinterpretation, misconstruction, mistake.
Use: Having money makes you happy is a fallacy because happiness has nothing to do with wealth.
Mark’s fallacy on the workings of the stock market caused us all to lose a great deal of money.