What does the word "hazardous" most closely relate to?

The term "hazardous" is primarily associated with risk or danger. In various contexts, such as environmental science, workplace safety, and public health, the word denotes something that poses a significant risk of harm or injury. For example, hazardous materials are substances that can cause serious health issues or environmental damage if improperly handled. Therefore, when one considers the meaning of "hazardous," it directly aligns with the notion of something that is dangerous, suggesting the potential for adverse outcomes.

The other choices do not accurately capture the essence of "hazardous." "Safe" implies a lack of danger, which contradicts the meaning of hazard. Similarly, “unknown” and “uncertain” relate more to the lack of information or clarity, rather than directly indicating a risk or danger. Thus, the best match for "hazardous" is indeed "dangerous," as it succinctly conveys the inherent risks associated with the term.