"Preëmptor" is a term used to describe someone who has taken a step ahead of others in order to prevent or thwart their plans. Synonyms for preëmptor include "interceptor," "disruptor," "preventer," and "obstructer." These words all bring to mind an individual who is actively engaging in stopping something from happening before it can even start. Other synonyms include "hurdler," "blocker," and "halter," which all suggest a sense of physical or mental obstacle that is being put in place to halt progress. Regardless of the synonym used, the idea of a preëmptor is someone who is willing to take bold action to prevent things from happening in order to protect their own interests.