An appearance of truth that is false or deceptive; seeming plausibility:
— The speciousness of his argument.

synonym: meretriciousness.

Roget 477: intuition, instinct, association, hunch, gut feeling; presentiment, premonition; rule of thumb; superstition; astrology^†; faith (supposition) 514.    sophistry, paralogy^†, perversion, casuistry, jesuitry, equivocation, evasion; chicane, chicanery; quiddet^†, quiddity; mystification; special pleading; speciousness etc. adj.; nonsense etc. 497; word sense, tongue sense.    false reasoning, vicious reasoning, circular reasoning; petitio principii [Lat.], ignoratio elenchi [Lat.]; post hoc ergo propter hoc [Lat.]; non sequitur, ignotum per ignotius [Lat.].    misjudgment etc. 481; false teaching etc. 538.    sophism, solecism, paralogism^†; quibble, quirk, elenchus^†, elench^†, fallacy, quodlibet, subterfuge, subtlety, quillet^†; inconsistency, antilogy^†; a delusion, a mockery, and a snare" [Denman]; claptrap, cant, mere words; lame and impotent conclusion" [Othello]. meshes of sophistry, cobwebs of sophistry; flaw in an argument; weak point, bad case.    overrefinement^†; hairsplitting etc. v.. ... show more