Tumefy, which means to swell or enlarge, is a unique word with a limited number of antonyms. Some possible antonyms include to diminish, deflate, reduce, contract, and shrink. Each of these words suggests a reduction in size, volume, or intensity. Other antonyms might include terms like deflate, collapse, impede, or hinder, which could indicate a decrease in energy, intensity, or speed. Some more abstract antonyms might include terms like apathy, indifference, or nonchalance, which could suggest a lack of emotion or enthusiasm. Ultimately, the choice of appropriate antonyms for tumefy will depend on the context in which the word is being used, and the nuances of the particular situation.