The term "mustard agent" is commonly used to describe a type of chemical warfare agent that is damaging and highly toxic. However, there are several other synonyms that are used to describe this class of agents, including sulfur mustard, Yperite, H, and HD. These agents are known for their ability to cause severe burns, blindness, and pulmonary damage in the individuals who are exposed to them. Despite being banned under the Chemical Weapons Convention, mustard agents have been used in various conflicts throughout history, making it crucial to understand and recognize their various synonyms and characteristics to prevent future exposure and harm.