0 relating to a philosophy (= system of ideas) according to which the world has no meaning and each person is alone and completely responsible for his or her own actions:
As a young artist not knowing how to define himself, he faced an existential crisis.
French philosophers even described what the footballer had done as being an existential act.
He said that, though a serious concern, terrorism shouldn’t be thought of as an existential threat.
It's an exaggeration to say he poses an existential danger to democracy.
