Dictionary and Thesaurus

Definition of Infallible

• (a.) Not fallible; not capable of erring; entirely exempt from liability to mistake; unerring; inerrable.
• (a.) Not liable to fail, deceive, or disappoint; indubitable; sure; certain; as, infallible evidence; infallible success; an infallible remedy.
• (a.) Incapable of error in defining doctrines touching faith or morals. See Papal infallibility, under Infallibility.

Synonyms of Infallible

• Necessary
• Essential
• Required
• Unavoidable
• Indispensable
• Needed
• Requisite
• Undeniable
• Inevitable
• Needful
• Foolproof
• Unfailing
• Inerrable
• Inerrant
• Unerring

Antonyms of Infallible

• Unreliable
• Undependable
• Errant
• Error-Prone
• Fallible
• Erring
• Non-Essential
• Unnecessary
• Worthless
• Weak
• Casual
• Needless
• Optional
• Useless
• Contingent

Homophones of Infallible