I bet almost everyone who uses existential cannot define it. It just sounds sophisticated and haughty.
Even the definition sounds like a Kamala word salad.
1. Of, relating to, or dealing with existence.
2. Based on experience; empirical.
3. Of or as conceived by existentialism or existentialists.
Maybe a Venn diagram would help.
EC
I first read the word many years ago as used by Søren Kierkegaard, "a 19th-century Danish philosopher who has been labeled by many as the "Father of Existentialism." His philosophy also influenced the development of existential psychology."
I did not find what little read to be interesting.