from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Incapable of erring: an infallible guide; an infallible source of information.
- adj. Incapable of failing; certain: an infallible antidote; an infallible rule.
- adj. Roman Catholic Church Incapable of error in expounding doctrine on faith or morals.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Without fault or weakness; incapable of error or fallacy.
- adj. certain, sure.
from the GNU version of the Collaborative International Dictionary of English
- adj. Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.
- adj. Not liable to fail, deceive, or disappoint; indubitable; sure; certain
- adj. Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.
from The Century Dictionary and Cyclopedia
- Not fallible in knowledge, judgment, or opinion; exempt from fallacy or liability to error; unerring.
- Unfailing in character or effect; exempt from uncertainty or liability to failure; absolutely trustworthy.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. incapable of failure or error
Middle English, from Medieval Latin īnfallibilis : Latin in-, not; see in-1 + Medieval Latin fallibilis, fallible; see fallible.(American Heritage® Dictionary of the English Language, Fourth Edition)
From Medieval Latin infallibilis, from Latin in- + fallibilis. Compare French infaillible. (Wiktionary)