foolproof
UK: ˈfuːlpruːf | US: ˈfuːlpruːf
adj. designed to be impossible to misuse or fail; infallibly simple or effective
The word "foolproof" emerged in the early 20th century, combining "fool" (from Old French "fol," meaning "unwise") and "proof" (from Latin "probare," meaning "to test or resist"). The logic is straightforward: if something is resistant to ("proof against") even a fool's mistakes, it is inherently reliable. This reflects a practical engineering or design philosophy aimed at minimizing human error.
The new software features a foolproof interface for beginners.
Her instructions were so clear and foolproof that no one made a mistake.
The safety mechanism is foolproof, preventing accidents even with improper use.
They designed a foolproof system to avoid data loss.
His plan seemed foolproof, but unexpected complications arose.