Where does “infallibly” come from?

Infallibly comes from Latin infallibilis, formed from the prefix in- and fallibilis, ultimately deriving from Proto-Indo-European roots meaning "not" and "to deceive."

infallibly (English): In an infallible manner

Definitions

  1. In an infallible manner

Ancestry of “infallibly”, step by step

StepLanguageWordMeaning
1EnglishinfallibleWithout fault or weakness; incapable of error or...
2Medieval Latinīnfallibilis
3Latinīn-un-, non-, not
4Latinînin, at, on, upon, from (space)
5Latinenlookǃ beholdǃ; reallyǃ?; come onǃ
6Proto-Italicenin
7Proto-Indo-Europeanh₁énin
Every word from Proto-Indo-European h₁én
infallibly — Etymology, Origin & Word History | Etymology Explorer