INFALLIBLE
infallible
(adjective) incapable of failure or error; “an infallible antidote”; “an infallible memory”; “the Catholic Church considers the Pope infallible”; “no doctor is infallible”
Source: WordNet® 3.1
Etymology
Adjective
infallible (comparative more infallible, superlative most infallible)
Without fault or weakness; incapable of error or fallacy.
Certain to produce the intended effect, sure.
Synonyms
• faultless
• perfect
• indefective
Antonyms
• fallible
• defective
• faultful
• faulty
• imperfect
• error-prone
Source: Wiktionary
In*fal"li*ble, a. Etym: [Pref. in- not + fallible: cf. F.
infallible.]
1. Not fallible; not capable of erring; entirely exempt from
liability to mistake; unerring; inerrable. Dryden.
2. Not liable to fail, deceive, or disappoint; indubitable; sure;
certain; as, infallible evidence; infallible success; an infallible
remedy.
To whom also he showed himself alive, after his passion, by many
infallible proofs. Acts i. 3.
3. (R. C. Ch.)
Definition: Incapable of error in defining doctrines touching faith or
morals. See Papal infallibility, under Infallibility.
Source: Webster’s Unabridged Dictionary 1913 Edition