Antonyms of adj infallible

1 sense of infallible

Sense 1
infallible (vs. fallible) -- (incapable of failure or error; "an infallible antidote"; "an infallible memory"; "the Catholic Church considers the Pope infallible"; "no doctor is infallible")

fallible (vs. infallible) -- (likely to fail or make errors; "everyone is fallible to some degree")
        => errant -- (straying from the right course or from accepted standards; "errant youngsters")
        => erring, error-prone -- (capable of making an error; "all men are error-prone")
        => undependable, unreliable -- (liable to be erroneous or misleading; "an undependable generalization")
        => weak -- (likely to fail under stress or pressure; "the weak link in the chain")

Similarity of adj infallible

1 sense of infallible

Sense 1
infallible (vs. fallible) -- (incapable of failure or error; "an infallible antidote"; "an infallible memory"; "the Catholic Church considers the Pope infallible"; "no doctor is infallible")
       => foolproof, unfailing -- (not liable to failure; "a foolproof identification system"; "the unfailing sign of an amateur"; "an unfailing test")
       => inerrable, inerrant, unerring -- (not liable to error; "the Church was...theoretically inerrant and omnicompetent"-G.G.Coulton; "lack an inerrant literary sense"; "an unerring marksman")