foolproof
Meaning
so simple, reliable, or well-designed that it cannot be misused or fail.
Structure
Usage
the instructions were designed to be completely foolproof.
they developed a foolproof security system for the data.
no plan is entirely foolproof, but this one comes close.
Etymology
the word 'foolproof' is a modern english compound, first attested in the early 20th century. it combines 'fool', a term for an unwise or incompetent person, with the suffix '-proof', which denotes protection or immunity against something. the literal construction means "proof against a fool," implying that a device or system is so ingeniously simple that even a fool's incompetence cannot cause it to fail. this compound follows a productive english pattern (like 'waterproof' or 'fireproof') to create adjectives describing resilience, here applying it humorously to human error rather than elemental forces.
Analysis
fool (from latin follis, meaning 'bellows, windbag', via old french fol, meaning 'madman, idiot'; functional role: base noun denoting a foolish person). proof (from latin probare, meaning 'to test, prove', via old french preuve; functional role: adjective-forming suffix meaning 'resistant, impervious').