Personality can be defined as consistency in a person's way of perceiving, thinking, acting, and reacting. It is shaped by heredity, environment, and other factors. Personality can be measured through observer ratings, self-reports, and assessments like the Myers-Briggs Type Indicator and Big Five personality model. The Big Five identifies five key traits - Extraversion, Agreeableness, Conscientiousness, Emotional Stability, and Openness to Experience - that can predict behaviors. Understanding personality and traits like Core Self-Evaluation, Machiavellianism, and Risk Taking can help with hiring, managing employees, and organizational implications.