FALLA'CIOUS, adjective [Latin 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.