Synonyms for fallacy

noun

1. An error in reasoning

   inconsistency, illogicality, sophism, sophistry, casuistry, quibble, quibbling, evasion, deceit, deception, delusion, equivocation, subterfuge, Jesuitry, misinterpretation, erroneousness, inexactness, error, deviation from truth, perversion, bias, prejudice, preconception, non sequitur, deceptive belief, deceptiveness, aberration, falsity, false notion, misleading appearance, illusion, speciousness, equivoke, artifice, ambiguity, solecism, paradox, miscalculation, quirk, flaw, cavil, irrelevancy, erratum, invalidity, heresy, heterodoxy.

   Antonyms logic*, reason*, law*.

2. A mistaken idea

   misconception, misapprehension, delusion; see error 1, mistake 2.