What is the closest meaning of the word "mitigate"?

The word "mitigate" refers to the action of making something less severe, serious, or painful. Therefore, "alleviate," which means to lessen or relieve (especially in terms of pain or hardship), closely aligns with the meaning of "mitigate."

In this context, both terms emphasize reducing the severity of a negative condition. For example, one might mitigate the impact of an illness by taking medication to alleviate symptoms. The focus on reducing distress or discomfort makes "alleviate" the most fitting synonym for "mitigate."

The other options do not share this meaning: "dishearten" conveys a sense of causing someone to lose confidence or enthusiasm, which is unrelated to the concept of reduction or relief. "Remiss" refers to being negligent in one's duties, while "uneasy" denotes a sense of discomfort or anxiety. None of these words suggest a similar approach to lessening severity, further highlighting why "alleviate" is the most appropriate answer.