Middlebreaker is quite a specific term, commonly used in the domain of agriculture, referring to the central point of a large field where the plowing begins and ends. When it comes to synonyms, one can use "furrow opener," "central plow" or "breakback plow" interchangeably with the word middlebreaker. Additionally, in a broader sense, terms like "pioneer," "trailblazer," or "leader" can be used to describe someone who clears the path for progress or introduces new ideas, concepts, and breakthroughs. Similarly, "mediator," "negotiator," or "arbiter" can describe a person who intervenes between two opposing parties to bring harmony or resolution in the middle.