The adjective combustible means something that ignite easily.

Synonyms are flammable, fiery, volatile, or explosive.

The word origins from Middle French (1798) combustible, or directly from Late Latin combustibilis and Latin combustus, past participle of combuere meaning “to burn up, consume”. Its figurative sense “easily excited” is from 1640s. As a noun, its meaning “a substance that will burn” is from 1680s.

It is highly combustible! Be careful!

A combustible material catches fire easily.

I changed the topic and moved to less combustible one.