The word "conflagrating" means to burn or ignite something. Some antonyms for this word could be extinguish, douse, smother, or dampen. Extinguish means to put out a fire or light, douse means to pour water onto something to extinguish a flame or fire, smother means to cut off the supply of oxygen to a flame, and dampen means to reduce the intensity of a flame or fire by adding water or other liquid. These words are all opposite to the idea of something burning or being on fire, and are useful for writing about fire fighting or prevention.