instigation vs trigger

instigation and trigger both are nouns.

Word	Noun	Adjective	Verb	Adverb
instigation	Yes	No	No	No
trigger	Yes	No	Yes	No

As nouns, trigger is a hypernym of instigation; that is, trigger is a word with a broader meaning than instigation:

Other hypernyms of instigation include induction, initiation.

instigation (noun)	trigger (noun)
deliberate and intentional triggering (of trouble or discord)	an act that sets in motion some course of events
the verbal act of urging on	lever that activates the firing mechanism of a gun
	a device that activates or releases or causes something to happen

instigation (verb)	trigger (verb)
	release or pull the trigger on
	put in motion or move to act