1. An issue, topic, or person that makes no progress or shows little evidence of future success. I know you worked really hard on that proposal, but it's a non-starter—the committee refuses to even consider it. You want to be a doctor? Boy, that's a non-starter—you can't even handle the sight of blood! I wouldn't have too much faith in Bobby—he's a nonstarter, and this business will probably just become another in a long line of failures for him.

2. sports One who does not start the game or race. This phrase is often used in horse racing. I watched the race—what happened to our horse? Why was he a non-starter? I may be a non-starter now, but my goal is to supplant the first-string quarterback in time.