A method or means (of doing something) that is certain to work, be effective, or have a particular outcome. Usually followed by "of" or "to." "Surefire" is sometimes hyphenated. Coming in to work drunk is a surefire way to get yourself fired, Tom. We've developed a sure-fire way of teaching grammar to grade-schoolers that they will not ignore or forget. A: "I hate scrubbing the dishes, so you better be right about this." B: "Trust me, this is a surefire way to keep food from sticking to your pans.