A lot vs. Alot: 9 Grammatical Pitfalls
1520s, from Middle French combustible, or directly from Late Latin combustibilis, from Latin combustus, past participle of combuere "to burn up, consume" (see combustion). Figurative sense is from 1640s; as a noun, from 1680s. Related: Combustibility (late 15c.).
combustible com·bus·ti·ble (kəm-bŭs'tə-bəl)
Capable of igniting and burning. n.
A substance that ignites and burns readily.