Defervescent refers to the reduction of fever. Some synonyms for defervescent include febrifugal, antipyretic, and afebrile. Febrifugal is a medication that is used to lower fever. An antipyretic is also a medication that is used to reduce fever and may include aspirin, acetaminophen, and ibuprofen. Afebrile refers to the state of being without a fever. In medical terms, the opposite of defervescent is febrile, which refers to the presence of fever. Additional synonyms for defervescent may include cooling, calming, and soothing, as these words describe the effect of defervescence on the body.