infallible
UK[ɪnˈfæləbl̩]US[ɪnˈfæləbl̩]
adj
incapable of making mistakes or being wrong.
adj
never failing; always effective.
Morpheme Breakdown
in
fall
ible
in
not
fall
deceive, err
ible
capable of
Etymology
the word "infallible" is a direct borrowing from medieval latin infallibilis. it is constructed from the latin negative prefix in- combined with the verb fallere, which meant "to deceive, to lead astray, to disappoint". the suffix -ibilis forms adjectives indicating capability. thus, the literal construction is "not capable of being deceived or making an error". this meaning evolved from the concrete sense of avoiding a deceptive trap to the more abstract concept of absolute certainty and reliability, free from fault or failure.
Analysis
Structure: in (not) + fall (deceive, err) + ible (capable of)
- in: latin origin, a prefix meaning "not".
- fall: from latin fallere, meaning "to deceive, to err, to disappoint". it is a direct substring of the english spelling.
- ible: latin suffix -ibilis, meaning "capable of, able to be".
Examples
the pope is considered infallible when speaking on matters of faith and morals.
no method of weather prediction is completely infallible.
he had an infallible knack for remembering names and faces.