Liable to burn essentially refers to objects or substances that are prone to catching fire easily. There are several synonyms for this term, including flammable, combustible, ignitable, and incendiary. These words are commonly used in warning signs, safety manuals, and labels of products that can be hazardous in terms of fire safety. Flammable refers to substances that are easy to ignite and can quickly spread fire. Combustible is another term that indicates how easily a substance can catch fire. Ignitable denotes substances that can ignite with ease and require special precautions for handling and storage. Lastly, the term incendiary refers to substances designed to cause fires or be used intentionally for arson.