Existential means of or relating to existence. It’s not to be confused with the adjective existentialist, which means of or relating to existentialism (i.e., a set of philosophical beliefs emphasizing subjective meaning and personal experience). Some dictionaries list existential as a variant of existentialist, but the words are generally kept separate in edited writing.
Existential appears in a few common phrases. An existential crisis is a period of intense questioning about one’s own existence. An existential threat is a threat to something’s survival. An existential question is a probing, philosophical question that gets down to the nature of what we are or why we are here.
Elsewhere, existential is often thrown around meaninglessly or used in odd ways. For example, this writer treats existential as a synonym of philosophical:
A loss will likely cause a minor existential crisis … For the United States, the crisis will be as tangible as existential. [Fox News]
An existential crisis may raise philosophical questions, but anything that involves one’s very existence is far from intangible. Plus, the phrase minor existential crisis is illogical because an existential crisis is by definition major.
The term existential threat is especially overused. If a threat does not endanger something’s existence, then it isn’t existential, even if it is a very serious threat. For example, existential creates an overstatement in these cases:
These trends pose an existential threat to Long Island, endangering our children’s health, our island ecosystem, our tourism and fishing industries. [Manhasset Press]
It is not just an unplanned vacation, it is an existential threat to your standard of living. [Zacks]
Let’s look at some positive examples. In these sentences, existential works because it means of or relating to existence:
Lake Pepin … is facing an existential problem: in a few hundred years it may no longer exist. [Twin Cities Daily Planet]
Bronstein might have gone on to look for those “nonevident concepts” instead of space and time, but first he had to deal with an existential problem in cosmology. [Scientific American]
Aside from longevity, it’s nowhere near the magnitude of World War II, which posed an existential threat … [Pocono Record]