Flameless is a word that describes something that lacks a flame or fire. There are several synonyms that can be used instead of flameless, such as non-flammable, spark-free, smokeless, and extinguished. Non-flammable refers to something that cannot catch fire, while spark-free describes something that does not produce sparks. Smokeless means that no smoke is emitted, while extinguished means that a fire has been put out. Other synonyms for flameless include quenched, out, and doused. Whatever synonym you choose to use, be sure to use it correctly to convey the intended meaning and avoid confusion.