trigger vs trigger off

trigger is a noun but trigger off is not a noun.

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

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

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

trigger (noun)	trigger off (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

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