EN

Synonyms for infallible

13 synonyms
7 antonyms

adjective

Most common

foolproof unfailing unerring inerrant flawless impeccable faultless inerrable

All synonyms

Adjective

inerrant, unerring, perfect, unfailing, foolproof, impeccable, flawless, faultless, sure, necessary, certain, inerrable, indefective

Antonyms

fallible, error-prone, imperfect

All antonyms of infallible →

Definitions

adj. 1
Without fault or weakness; incapable of error or fallacy.
He knows about many things, but even he is not infallible.

Related words

Word family: infallibleness infallibility

Choose the right word

or Infallible?

An infallible proof is one that necessarily leads the mind to a sound conclusion.

J. C. Fernald, English Synonyms and Antonyms (1914)

Example sentences

foolproof They designed their plan to be foolproof.
unfailing Unfailing love does not exist.
flawless Tom's flawless and nobody can find a fault in him.
impeccable The service at Benedito's restaurant is impeccable.

Popularity over time

Word	1850 → 2019	Trend
infallible		steady
foolproof		steady
unfailing		steady
unerring		steady
inerrant		rising
flawless		rising

Use in printed books, per decade from 1850 to 2019.

By length

4 letters: sure¹
7 letters: perfect², certain²
8 letters: flawless², unerring, inerrant
9 letters: necessary⁴, foolproof², faultless, unfailing³, inerrable
10 letters: impeccable⁴
11 letters: indefective

The small number after each word is its number of syllables (perfect² = 2 syllables).

In other languages

Français: infaillible
Italiano: infallibile