Phobia, an intense, persistent, abnormal fear of an object, act, or situation. The person with a phobia may be aware that the fear is unrealistic, but is unable to control it. If confronted with the feared object or situation, the person becomes extremely agitated and may collapse.

According to most psychiatrists and psychologists, the feared object or situation is a symbol for an unconscious fear that the sufferer has repressed as too painful to accept. This unconscious fear is often of the individual's own aggressive feelings stemming from early childhood. A frightening experience may have become linked to the unconscious fear, resulting in the phobia. Some common phobias are claustrophobia (fear of closed places), acrophobia (heights), zoophobia (animals), and nyctophobia (darkness). Phobias are sometimes successfully treated by psychotherapy.