Sizzes is not a standard word in the English language, and hence, it does not have any direct antonyms. However, based on the context in which one may use the word, it may be helpful to explore antonyms related to similar-sounding words. For instance, if by sizzes, one is referring to a high-pitched, hissing sound, then some antonyms could be silence, quietness, or stillness. Alternatively, if by sizzes, one is referring to the act of a flame or fire making a crackling sound, then antonyms could be calm, tranquil, or placid. Overall, it is essential to consider the context in which the word sizzes is used to understand any potential antonyms.