Exacerbate is a term that typically implies the worsening or intensification of a situation or condition. Its antonyms (words with an opposite meaning) would be those that imply reducing or alleviating, such as ameliorate, ease, relieve or soothe. Other antonyms could be those that imply avoidance or prevention, such as avert, prevent or circumvent. Alternatively, opposite words like assuage, mollify, pacify could imply the calming or appeasing of the situation. Depending on the context, one could use these antonyms to effectively communicate the desired outcome of an action or situation.