foolproof

Of a device: protected against, or designed to be proof against, misuse or error.

Adjective

Of a device: protected against, or designed to be proof against, misuse or error.
Of an idea or plan: certain to succeed in all eventualities, or claimed to be so; infallible.
- Dill had hit upon a foolproof plan to make Boo Radley come out at no cost to ourselves (place a trail of lemon drops from the back door to the front yard and he’d follow it, like an ant). - 1960 July 11, Harper Lee,...
- My foolproof recipe is my gâteau fermière. - 2021 June 1, Marie-Dominique, “‘Throw the ingredients together with reckless abandon!’: Guardian readers on their tastiest foolproof bakes”, in The Guardian, archived from...
- From Nigella Lawson’s effortless spaghetti with Marmite to Chetna Makan’s foolproof chicken curry – the recipes to turn to when you want easy but tasty suppers - 2022 January 24, Allan Jenkins, Molly Tait-Hyland, “The...