From Longman Dictionary of Contemporary Englishfoolprooffool‧proof /ˈfuːlpruːf/ ●○○ adjective CERTAINLY/DEFINITELYa foolproof method, plan, system etc is certain to be successful SYN infallible a foolproof way of preventing credit card fraud
Examples from the Corpus
foolproof• These tips are intended to help, but should not be regarded as foolproof.• The key, here, was not kept under a flowerpot or stone but in a more foolproof and elaborate hiding-place.• The new speech recognition system is not absolutely foolproof, but it is a huge breakthrough.• Even so, marriage is hardly a foolproof enforcer of monogamy.• First, no technology is foolproof, especially electronic technology; we still need very old-fashioned backup systems.• The foolproof fuel system has interconnected front and rear fuselage flexible tanks holding 255 and 475 litres.• A pasta book is a foolproof gift for anyone who cooks.• Condoms aren't a foolproof method of preventing pregnancy.• Each article goes through a foolproof system of checking which ensures that there are no mistakes in the final text.• I thought this method was foolproof until four customer orders went missing.• It's foolproof, watertight, totally convincing.• The gang hit on a seemingly foolproof way of getting drugs into the country.• There's no foolproof way to judge whether someone is the right person for the job. 