Ambustion is a rarely used term that refers to burning or scorching. Some common synonyms that can be used in its place include combustion, incineration, immolation, ignition, and flare-up. Combustion and incineration typically refer to the process of burning something completely, such as in a furnace or engine. Immolation is generally reserved for intentionally setting something on fire, often as part of a religious or political ritual. Ignition and flare-up both refer to sudden bursts of flames, with ignition suggesting a deliberate action and flare-up suggesting an unexpected or unintended event. By choosing the right synonym for the situation, you can more effectively communicate the intended meaning of a sentence.