Which word would best describe a person who is excessively hostile towards others?

The word "truculent" is an excellent choice to describe a person who is excessively hostile towards others. This term specifically refers to a fierce, aggressive, or combative attitude, often characterized by a readiness to fight or be confrontational. In behavioral contexts, a truculent individual is one who displays a penchant for hostility and aggression, making it fitting for someone described as excessively hostile.

In contrast, the other terms have meanings that are antithetical to hostility. "Supportive" refers to a helpful and caring disposition, often characterized by encouragement and assistance towards others. "Laudative" pertains to expressing praise or admiration, which is not compatible with hostility at all. "Diplomatic" describes a person who is tactful and skilled in dealing with sensitive situations or conflicts, promoting peace and understanding rather than hostility. Thus, "truculent" stands out as the suitable descriptor for someone exhibiting excessive hostility.