In modern English usage, the informal term idiot proof or foolproof describes designs which cannot be misused either inherently, or by use of defensive design principles. The implication is that the design is usable even by someone of low intelligence who would not use it properly. The term fool proof originates in 1902. The term idiot proof became popular in the 1970s. It may have been invented as a stronger-sounding version of foolproof, as the force of foolproof had declined due to frequent usage. Perhaps for the same reason, 'foolproof' is now a formal term, whereas 'idiot proof' remains informal...