infallible
adj.adj. never making mistakes and always being right. It describes someone or something that is perfect and cannot fail.
adj. incapable of making errors or being wrong. Often used to describe systems, logic, or authorities that are considered beyond question.
No human being is truly infallible.
The scientist admitted that even the most advanced computer models are not infallible and can produce incorrect results.
While the leader projected an image of being infallible, the subsequent collapse of the policy revealed deep flaws in his initial reasoning.
From Medieval Latin infallibilis, from Latin in- + fallibilis. Compare French infaillible. By surface analysis, in- + fallible.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Often used predicatively after linking verbs like 'be' or 'seem'.
Last updated May 11, 2026