foolproof
US
UK foolproof adj: (that cannot be misused)
SC 使用简单方便的 shǐ yòng jiǎn dān fāng biàn de
Canned gravy is foolproof because you don't even have to mix any ingredients!
foolproof adj: (that cannot fail)
SC 万无一失的 wàn wú yì shī de
SC 不会出毛病的 wàn wú yì shī de，bú huì chū máo bìng de
This is a foolproof way to curl your hair.