Synonyms for infallible
modified
unerring, exact, perfect, unfailing, faultless, sure, reliable, dependable, trustworthy, unquestionable, true, authoritative, positive, irrefutable, apodictic, incontrovertible, fail-safe, sure-fire*; see also accurate 1, 2, certain 3.
Antonyms false*, fallible, unreliable.
See infallible in Webster's New World Roget's A-Z Thesaurus II
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