A skeptic is a doubter. The one who can't be convinced. The guy who's ready to poke holes in the most brilliant argument you've ever made.
For every great idea, there are probably 100 skeptics waiting to shoot it down. These are the naysayers that didn't think rock music would last, questioned the usefulness of seat belts, and even wondered if the internet would catch on. Coming from the Greek word skeptikos, which means "thoughtful or inquiring," it's no surprise that a skeptic is someone who asks a lot of questions — and isn't easily convinced, even by the smartest answers.