fallacious C2+ Topic:Describing Qualities US /fəˈleɪʃəs/ UK /fəˈleɪʃəs/ See IPA manual Meanings 1 adj based on a mistaken belief or unsound reasoning His argument rests on a fallacious comparison. Thesaurus Synonyms 1 adj · based on a mistaken belief... erroneousmisleadingspuriousunsounddeceptivespeciousfalseillogical ↔ Opposites validsoundcorrecttruelogical Word family Forms fallaciouslyfallaciousness Derived forms fallaciouslyfallaciousness Related forms fallacyfailfallible Etymology AI details From Latin 'fallāx' (stem 'fallāci-', 'deceptive'), from 'fallere' ('to deceive, disappoint'), via the English suffix '-ous'. fallāx Latin fallere Latin View etymology graph -> Topics Describing Qualities Word Formation & Derivatives External links Google Images Cambridge Dictionary Wiktionary # fallacious **Type:** Word **Level:** C2+ **Part of speech:** adj **IPA (US):** /fəˈleɪʃəs/ **IPA (UK):** /fəˈleɪʃəs/ ## Meanings 1. based on a mistaken belief or unsound reasoning ## Examples - His argument rests on a fallacious comparison. ## Synonyms - erroneous - misleading - spurious - unsound - deceptive - specious - false - illogical ## Antonyms - valid - sound - correct - true - logical ## Derived Forms - fallaciously - fallaciousness ## Related Forms - fallacy - fail - fallible ## Roots and Affixes - Root: fallāx - Root: fallere ## Etymology From Latin 'fallāx' (stem 'fallāci-', 'deceptive'), from 'fallere' ('to deceive, disappoint'), via the English suffix '-ous'. ## AI Etymology Fallacious is from Latin 'fallāx' (stem 'fallāci-', 'deceptive'), from 'fallere' ('to deceive, disappoint'), via the English suffix '-ous'. Important recorded forms include fallāx (Latin) and fallere (Latin). Morphologically, the word is a built form whose named elements carry part of the historical sense. The current sense covers based on a mistaken belief or unsound reasoning. The wider family includes derived forms such as fallaciously and fallaciousness and related words such as fallacy, fail, and fallible. ## Topics - Describing Qualities - Word Formation & Derivatives markdown