In modern English usage, the term "idiot proof" describes designs which inherently or by use of defensive design principles cannot be misused. The implication is that the design is usable even by someone of low intelligence who would not use it properly. The term came into use in the late 1970s to early 1980s. A similar term is foolproof, introduced in 1902.[1] Idiot proof is an informal term; foolproof is often used in a more formal context. Both terms are originally adjectives ("a foolproof plan"), but can be used as verbs ("foolproof this design").