Psychologists generally agree that wisdom is learned from experience rather than the explicit knowledge obtained from lectures and books.
Psychologist Robert J. Sternberg developed a balance theory of wisdom. Following is his definition.
The balance theory defines wisdom as the use of one’s intelligence, creativity, commone sense, and knowledge and as mediated by positive ethical values toward the achievement of a common good through a balance among (a) intrapersonal, (b) interpersonal, and (c) extrapersonal interests, over the (a) short and (b) long terms to achieve a balance among (a) adaptation to existing environments, (b) shaping of existing environments, and (c) selection of new environments. (Sternberg, n.d.)