adj.
Pronunciation: ( ˌ )in- ' fa-l ə -b ə l
Function: adjective
Etymology: Middle English, from Medieval Latin infallibilis, from Latin in- + Late Latin fallibilis fallible
Date: 15th century
1 : incapable of error : UNERRING <an infallible memory>
2 : not liable to mislead, deceive, or disappoint : CERTAIN <an infallible remedy>
3 : incapable of error in defining doctrines touching faith or morals
– in · fal · li · bil · i · ty \ - ˌ fa-l ə - ' bi-l ə -t ē \ noun
– in · fal · li · bly \ - ' fa-l ə -bl ē \ adverb