fail-safe

剑桥词典

very unlikely to fail
萬無一失的，萬全的
a fail-safe plan 萬無一失的計劃

If something is fail-safe, it has been designed so that if one part of it does not work , the whole thing does not become dangerous .
可自動防止故障危害的；有自動保險裝置的
a fail-safe device 故障保護裝置 返回 fail-safe