combust vs ignite

combust and ignite both are verbs.

Word	Noun	Adjective	Verb	Adverb
combust	No	No	Yes	No
ignite	No	No	Yes	No

As verbs, combust and ignite are synonyms defined as:

Other synonyms of combust include catch fire, conflagrate, erupt, take fire.

As verbs, ignite is a hyponym of combust; that is, ignite is a word with a more specific, narrower meaning than combust:

Other hyponyms of combust include light, set ablaze, set afire, set aflame, set on fire, char, coal, deflagrate.

combust (verb)	ignite (verb)
undergo combustion	start or maintain a fire in
get very angry and fly into a rage	arouse or excite feelings and passions
cause to become violent or angry	cause to start burning; subject to fire or great heat
start to burn or burst into flames	start to burn or burst into flames
cause to burn or combust