1. Behavior exhibiting excessive or uncontrollable emotion, such as fear or panic.

2. A group of psychiatric symptoms, including heightened emotionality, attention-seeking behavior, and preoccupation with physical symptoms that may not be explainable by a medical condition. The term hysteria is no longer in clinical use, and such symptoms are currently attributed to any of several psychiatric conditions, including somatic symptom disorder, conversion disorder, and histrionic personality disorder.