infallible

plural infallibles

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

comparative more infallible · superlative most infallible

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

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

   1 more example

   That there may be Certainty upon an infallible Evidence in Matters of Science, I readily grant you. But since there once were Scepticks in Philosophy as well as Religion, such as doubted of every thing, I very much question, whether the whole World be agreed in this Point; unless you could assure me, that Race of Seekers is now extinct.

   1720, Samuel Fancourt, “The Remarker's second Objection produced and examined”, in An Essay Concerning Certainty and Infallibility, London: R. Cruttenden, page 35

2. Certain to produce the intended effect; sure.

   Try this infallible cure for hiccups.

   2 more examples

   [L]isten patiently [...] and you will easily perceive why I am reserved upon that subject. I will not lead you on, unguarded and ardent as I then was, to your destruction and infallible misery.

   1818, Mary Shelley, chapter 4, in Frankenstein, archived from the original on 30 Oct 2011

   In precisely the same way does a quack doctor prescribe his infallible nostrum to every patient, without taking into account differences of constitution, or [...]

   1833, James Rennie, “The Word Gardening”, in Alphabet of Scientific Gardening for the Use of Beginners, London: William Orr, page 2

3. Certain to result from a specific cause; inevitable.

   Paley can only account for this fact by saying that we are constrained by the fear of punishment in a future life, such having been declared to us by revelation to be the infallible result of wrong action.

   1871, Alexander Grant, “On the Nature and Origin of the Moral Ideas”, in Papers Read at the Meetings of the Metaphysical Society

plural Infallibles

1. IslamAny of the fourteen central religious figures believed by Twelver Shia Muslims to be infallible, consisting of Muhammad, his daughter Fatima, and the Twelve Imams recognized by Twelvers.