foolproof

adj

• ① (规则、计划等)万无一失的,不会出差错的
  • a foolproof identification system万无一失的识别系统

• ② (机器等)极易操作的,极简易的
  • The machine was foolproof as drivers would be unable to alter the reading.由于驾驶者无法改变读数,所以这机器操作简易。