What does the term "adverse" imply regarding conditions or effects?

The term "adverse" is often used to describe conditions or effects that are harmful, unfavorable, or detrimental. When applied to medical or environmental contexts, "adverse" signifies negative outcomes that can cause harm or worsen a situation. For example, adverse reactions to medication can lead to serious health problems rather than improving a patient's condition. This aligns perfectly with the definition of the term, making it the most accurate choice in this context.