Foolproof and Sure-fire

Foolproof adjective - Not liable to failure.

Sure-fire and foolproof are semantically related in infallible topic. In some cases you can use "Sure-fire" instead an adjective "Foolproof". informal substitute

Sure-fire adjective - Certain to be successful.

Foolproof and sure-fire are semantically related in dependable topic. You can use "Foolproof" instead an adjective phrase "Sure-fire". popular alternative