n.1. a state of independence and self-determination in an individual, a group, or a society. According to some theories, an inordinate focus on self-determination and achievement represents a risk factor for the development of major depressive disorder. See also functional autonomy. Compare heteronomy. 2. in self-determination theory more specifically, the experience of acting from choice, rather than feeling pressured to act. This form of autonomy is considered a fundamental psychological need that predicts well-being.