fallacy \FAL-uh-see\,
noun:
1. a deceptive, misleading, or false notion, belief, etc.: That the world is flat was at one time a popular fallacy.
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.
"Mind you, I see the fallacy," he said. He liked the word. It was an honest admission of error.
-- George Friel, "The Boy Who Wanted Peace," 1964
Because it has been his practice to listen to all that could be said against him; to profit by as much of it as was just, and expound to himself, and upon occasion to others, the fallacy of what was fallacious.
-- John Stuart Mill, "On Liberty," 1859
Fallacy came to English in the 1300s from the Latin fallācia meaning "a trick."
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