Which term best conveys the idea of intimidating someone to discourage them?

The term that best conveys the idea of intimidating someone to discourage them is "daunt." To daunt someone means to make them feel apprehensive or afraid, often to the extent that they feel discouraged from taking action or pursuing something. This aligns perfectly with the notion of using intimidation as a method to dissuade or frighten someone.

The other options present different meanings: "culpable" refers to being deserving of blame or guilt, "curmudgeon" describes a person who is often ill-tempered or grouchy, and "debacle" denotes a sudden and ignominious failure or collapse. None of these alternatives capture the essence of intimidation that "daunt" embodies, making it the most fitting choice for the given definition.