foolproof

[ fool-proof ]

adjective

1. involving no risk or harm, even when tampered with.
2. never-failing:

   a foolproof method.

foolproof

/ ˈfuːlˌpruːf /

adjective

1. proof against failure; infallible

   a foolproof idea

2. (esp of machines) proof against human misuse, error, etc

Word History and Origins

Origin of foolproof¹

An Americanism dating back to 1900–05; fool ¹ + -proof

Example Sentences

Scotland Yard said it was let down by the security staff of Lloyds Bank, who in turn said they had been assured their alarms were "foolproof".

From BBC

While 2FA enhances security, it can also foster a false sense of confidence. 2FA seems foolproof, leading many people to pay less attention to other security practices, like using strong, unique passwords for each account.

From Salon

"That was clearly a foolproof plan given I'm reading those texts to you right now," Oliver joked.

From Salon

Also, safeguarding checks are not foolproof because they don't necessarily mean that suspects can't move into other organisations and perpetrate abuse.

From BBC

The plan seems foolproof — unless, of course, the incumbent doesn’t actually win the election.

From Los Angeles Times

Related Words

• flawless
• reliable
• surefire
• unassailable