Combustibly is an adverb that describes something being able to catch fire or burst into flames easily. Other synonyms for combustibly include inflammable, flammable, ignitable and explosive. These words all describe materials that can ignite and burn easily. Inflammable and flammable both refer to materials that are capable of catching fire and burning easily, while ignitable refers to the ability to be set on fire. Explosive refers to materials that produce an explosion or a sudden release of energy. When using these words, it is important to handle potentially dangerous materials with care and caution to avoid accidents or fires.