1. infallible - Noun
2. infallible - Adjective
Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.
Not liable to fail, deceive, or disappoint; indubitable; sure; certain; as, infallible evidence; infallible success; an infallible remedy.
Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.
Source: Webster's dictionaryCorruption, the most infallible symptom of constitutional liberty. Edward Gibbon
Golf... is the infallible test. The man who can go into a patch of rough alone, with the knowledge that only God is watching him, and play his ball where it lies, is the man who will serve you faithfully and well. P. G. Wodehouse
The only infallible rule we know is, that the man who is always talking about being a gentleman never is one. Robert Smith Surtees
Readiness to answer all questions is the infallible sign of stupidity. Saul Bellow
No man is infallible. Traditional Proverb
No man is infallible. English Proverb