FALLA'CIOUS, a. [L. fallax, from fallo, to deceive. See Fail.]
1. Deceptive; deceiving; deceitful; wearing a false appearance; misleading; producing error or mistake; sophistical; applied to things only; as a fallacious argument or proposition; a fallacious appearance.2. Deceitful; false; not well founded; producing disappointment; mocking expectation; as a fallacious hope.