Trait Theory:Trait theory is an approach to the study of personality that focuses on identifying and measuring individual differences in distinct and relatively stable personality characteristics or traits.
Personality Inventory: A personality inventory is a self-report assessment tool used to measure an individual's personality traits, attitudes, and behaviors, often based on the OCEAN model.
Personality Disorders:Personality disorders are a class of mental disorders characterized by inflexible and maladaptive personality traits that cause significant distress or impairment in social, occupational, or other areas of functioning.