Combust/kəmˈbʌst/ Definition 1 of 3Pro Tip 1/3Literal Burning Directly refers to something catching fire or being set on fire. Do not smoke here, as the dry leaves may combust. Pro Tip 2/3Natural Occurrence Describes fires that start without human intervention, often used in natural sciences. The forest can combust due to extreme heat during a drought. Pro Tip 3/3Immediate Danger Implies an imminent risk of fire, often used in safety warnings. Evacuate the area, as the chemicals may combust any moment.