set off vs trigger

set off is not a noun while trigger is a noun.

Word	Noun	Adjective	Verb	Adverb
set off	No	No	Yes	No
trigger	Yes	No	Yes	No

As verbs, set off and trigger are synonyms defined as:

Other synonyms of set off include activate, actuate, spark, spark off, touch off, trigger off, trip.

set off (noun)	trigger (noun)
	an act that sets in motion some course of events
	lever that activates the firing mechanism of a gun
	a device that activates or releases or causes something to happen

set off (verb)	trigger (verb)
cause to burst with a violent release of energy	release or pull the trigger on
set in motion or cause to begin	put in motion or move to act
direct attention to, as if by means of contrast
provoke or stir up
put in motion or move to act
depart for someplace
make up for