Agreeableness is a personality trait referring to individuals that are perceived as kind, sympathetic, cooperative, warm, honest, and considerate. In personality psychology, agreeableness is one of the five major dimensions of personality structure, reflecting individual differences in cooperation and social harmony.

In psychology, trait theory is an approach to the study of human personality. Trait theorists are primarily interested in the measurement of traits, which can be defined as habitual patterns of behavior, thought, and emotion. According to this perspective, traits are aspects of personality that are relatively stable over time, differ across individuals, are relatively consistent over situations, and influence behaviour. Traits are in contrast to states, which are more transitory dispositions.