Sure-fire and Surefire

Sure-fire adjective - Certain to be successful.

Surefire and sure-fire are semantically related In some cases you can use "Surefire" instead an adjective phrase "Sure-fire".

Surefire adjective - Not likely to fail.

Sure-fire and surefire are semantically related in infallible topic. You can use "Sure-fire" instead an adjective "Surefire", if it concerns topics such as made certain, easy to foretell.