1. The belief that you should reject anything proposed by another political party or group, no matter what it is or how it might benefit others.
2. A kneejerk reaction to anything that isn't "ideologically pure."
3. The attitude that you can honestly reject an idea even if you don't what it is -- or that you can reject a proposal without even reading it -- simply based on its origin.
Melvin is a perfect example of Rejectionism. He condemned the latest health care plan before it was even released -- in fact, before it was even written.