Individualism

Individualism refers to a broad philosophy that emphasizes the importance of the individual. Individualism is favor in individual decision and liberty, and has largely influenced liberalism, libertarianism, and of course (individualist) anarchism. Individualism also emphasize that each individual's liberty must not violate other individual's liberty.

Individualist/Egoist thinking had existed since the start of civilization, although the theorization of modern Individualism had only began during the enlightenment era.

Personality
Individualism is very individualistic, whatever that means.