existentialism

noun

1. (uncountable)A 20th-century philosophical movement emphasizing the uniqueness of each human existence in freely making its self-defining choices.

   “The heyday of existentialism occurred in the mid-twentieth century.”

2. (countable)The philosophical views of a particular thinker associated with the existentialist movement.

   “Sartre's existentialism is atheistic, but the existentialism of Marcel is distinctly Christian.”

   “Instead of Existentialism, we should speak of Existentialisms.”