catch fire vs ignite

catch fire and ignite both are verbs.

Word	Noun	Adjective	Verb	Adverb
catch fire	No	No	Yes	No
ignite	No	No	Yes	No

As verbs, catch fire and ignite are synonyms defined as:

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

catch fire (verb)	ignite (verb)
start to burn or burst into flames	start or maintain a fire in
	arouse or excite feelings and passions
	cause to start burning; subject to fire or great heat
	start to burn or burst into flames