never wrong; never making mistakes 永无过失的；一贯正确的 that never fails; always doing what it is supposed to do 绝对可靠的；万无一失的 an infallible method of memorizing things 百试百灵的记忆方法
Word Originlate 15th cent.: from French infaillible or late Latin infallibilis, from in- ‘not’ + Latin fallere ‘deceive’.