trigger

verb

triggered; triggering ˈtri-g(ə-)riŋ 

transitive verb

1

a

: to release or activate by means of a trigger

especially : to fire by pulling a mechanical trigger

trigger a rifle

b

: to cause the explosion of

trigger a missile with a proximity fuse

2

: to initiate, actuate, or set off by a trigger

an indiscreet remark that triggered a fight

a stimulus that triggered a reflex

3

: to cause an intense and usually negative emotional reaction in (someone)

Water had a way of triggering my brother and making ordinary, everyday weather take a frightening turn for the worse.—Ingrid Law