The trait approach is a way of studying personality that places emphasis on the traits of an individual as markers of personality. Traits are continuing patterns of behavior and thoughts that are generally stable over time. Traits are often the things that people use to describe another person such as nice, rude, funny, honest. The trait approach suggests that our personalities are comprised of these differing behavioral traits.
The trait approach is focused on individual differences and the interaction and combination of personality traits are what makes individual personalities unique. Many different theories use this approach such as the Big Five personality factor theory and the work of Gordon Allport and Raymond Cattell. A critique of the trait approach for personality is that traits can sometimes be bad predictors of behavior. Just because a person scores high on a particular trait doesn't mean they will act that way in a real world setting.