Antonyms for the word "infallible" include words like fallible, erring, imperfect, uncertain, and flawed. All of these words imply the opposite of perfection or infallibility, suggesting that something can be incorrect or prone to error. A fallible person or system may make mistakes, whereas an infallible one cannot. Similarly, something that is uncertain or imperfect lacks the unassailable assurance that infallibility implies. Ultimately, antonyms for infallibility point to the inherent limitations of human knowledge and understanding, reminding us that nothing is truly flawless or unerring.