Existentialism (noun)

1. A philosophical movement emphasizing individual freedom and choice, and the inherent meaninglessness of life.
2. A philosophy that emphasizes the individual's unique position as a self-determining agent responsible for the authenticity of their own existence.

Origin:

French existentialisme, from existentiel, from existant, present participle of exister to exist, from latin existere.

Examples:

1. He studied existentialism in college.
2. The novel's main theme is existentialism.
3. The play explores the existentialism of the human condition.
4. She is an advocate of existentialism in her teaching.
5. He found solace in existentialism after the death of his wife.