'foolproof' definitions:

Definition of 'foolproof'

From: WordNet
adjective
Not liable to failure; "a foolproof identification system"; "the unfailing sign of an amateur"; "an unfailing test" [syn: foolproof, unfailing]
verb
Proof against human misuse or error; "foolproof this appliance" [syn: goofproof, goof-proof, foolproof]