in ‧ fal ‧ li ‧ ble /ɪnˈfæləb ə l, ɪnˈfælɪb ə l/ BrE AmE adjective
1 . always right and never making mistakes OPP fallible :
No expert is infallible.
an infallible memory
2 . something that is infallible always works or has the intended effect ⇨ fail-safe :
He had an infallible cure for a hangover.
—infallibly adverb
—infallibility /ɪnˌfæləˈbɪləti, ɪnˌfælɪˈbɪləti/ noun [uncountable]