The term "high sea" describes the open or unenclosed sea, which is unregulated territory beyond coastal waters or the jurisdiction of any particular government. There are several words that could be used as synonyms for "high sea," including the open sea, the deep waters, the vast ocean, the high seas, and the broad blue. Additional synonyms include the big drink, the great ocean, the main, and the wild. Other options might include descriptors such as the unbounded ocean, the limitless waves, and the boundless water. Ultimately, the choice of synonym may depend on the context and tone of the piece, as well as personal preference and style.