Where does “fallacious” come from?

Fallacious comes from Middle English -ous, Latin fallacia meaning deception, and Latin fallōsus, derived from Latin fallō meaning to deceive or disappoint.

fallacious (English): Characterized by fallacy; false or mistaken;...

Definitions

  1. Characterized by fallacy; false or mistaken;...

Ancestry of “fallacious”, step by step

fallacious traces back through 3 separate lines of ancestry.

via French fallacieux

StepLanguageWordMeaning
1Frenchfallacieuxfallacious
2Latinfallaciadeception, deceit
3Latinfallāxdeceptive, deceitful
4Latin-āxish, -y
5Latin-iumSuffix used to form abstract nouns, sometimes...
6Latin-iusforming adjectives from nouns; nominative neuter...
7Proto-Italic-jōsForms comparative adjectives
8Proto-Indo-European-yósCreates adjectives from noun or verb stems

via Middle English ous

StepLanguageWordMeaning
1Middle EnglishousAlternative form of us

via Middle English fallace

StepLanguageWordMeaning
1Middle Englishfallace

Words derived from “fallacious

Every word from Proto-Indo-European -yósEvery word from Latin -iumEvery word from Latin -ius
fallacious — Etymology, Origin & Word History | Etymology Explorer