instigative vs incendiary

instigative is not a noun while incendiary is a noun.

Word	Noun	Adjective	Verb	Adverb
instigative	No	Yes	No	No
incendiary	Yes	Yes	No	No

As adjectives, instigative and incendiary are synonyms defined as:

Other synonyms of instigative include incitive, inflammatory, rabble-rousing, seditious.

instigative (noun)	incendiary (noun)
	a bomb that is designed to start fires; is most effective against flammable targets (such as fuel)
	a criminal who illegally sets fire to property

instigative (adjective)	incendiary (adjective)
arousing to action or rebellion	involving deliberate burning of property
	capable of catching fire spontaneously or causing fires or burning readily
	arousing to action or rebellion