Conflagrate means to ignite or set ablaze. The word has no commonly used antonyms, but there are a few words that are opposite in meaning to it. Some of these antonyms are extinguish, douse, smother, put out, and quench, which mean to put out a fire or make something stop burning. However, these antonyms do not have the same intense opposite meaning as conflagrate. Another set of antonyms that could be used is the range of words that means to cool or freeze, such as freeze, cool, or chill, as these words are the complete opposite of conflagrate in every way possible.