fire-raising vs combustion

fire-raising and combustion both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire-raising	Yes	No	No	No
combustion	Yes	No	No	No

As nouns, combustion is a hypernym of fire-raising; that is, combustion is a word with a broader meaning than fire-raising:

Other hypernyms of fire-raising include burning.

fire-raising (noun)	combustion (noun)
malicious burning to destroy property	the act of burning something
	a process in which a substance reacts with oxygen to give heat and light
	a state of violent disturbance and excitement