Existentialism
Etymology
From Latin "existere," "to stand forth, exist." Its roots lie in the 19th-century writings of Søren Kierkegaard and Friedrich Nietzsche, but it became a named movement through Jean-Paul Sartre in the 1940s, who embraced the label and coined the slogan “existence precedes essence” — we exist first, then define what we are.
noun · /eg-zih-STEN-shuh-liz-um/
The philosophy that individuals are radically free and must create their own meaning and values through their choices, in a universe that supplies none.
What it names
A handle for the weight and freedom of self-authorship — the sense that no role, tradition, or nature decides who you are; your choices do.
Example
Quitting the family firm to paint was pure existentialism: she decided that her life would mean whatever she chose to make it mean.
Related idea
Essentialism is its direct opposite — the idea that things (including people) have a fixed nature that comes first. Existentialists insist there is no such pre-written essence to live up to.