adj, noun ·Moderate ·College level

Definitions

Noun

1. 1
   A person who, or an object or process that, is taken as being infallible.

Adjective

1. 1
   Without fault or weakness; incapable of error or fallacy.

   "He knows about many things, but even he is not infallible."

2. 2
   Certain to produce the intended effect; sure.

   "Try this infallible cure for hiccups."

Adjective

1. 1
   incapable of failure or error wordnet

Synonyms

All synonyms

faultlessfoolproofindefectiveinerrableperfectabsolute

Antonyms

All antonyms

error pronedefectiveerror-pronefallible

Example

More examples

"He believes himself to be infallible."

Etymology

From Medieval Latin infallibilis, from Latin in- + fallibilis. Compare French infaillible. By surface analysis, in- + fallible.

Data sourced from Wiktionary, WordNet, CMU, and other open linguistic databases. Updated March 2026.