Burn up Definition 1 of 4Pro Tip 1/3Complete Destruction Used when something has been destroyed by fire so thoroughly that nothing is left. The old barn burned up in the blaze. Pro Tip 2/3Strong Intensity Emphasizes the intensity of a fire or heat to the point of consuming completely. The papers in the fireplace will burn up quickly. Pro Tip 3/3Environmental Impact Reflects concern over excessive use of natural resources with a negative impact. We must avoid burning up our forests irresponsibly.