Final answer:
An intense fear reaction resembling sheer terror is called a panic attack. It is a sudden episode of intense fear accompanied by physical symptoms. Panic attacks are common in individuals with panic disorder.
Step-by-step explanation:
An intense fear reaction resembling sheer terror is called a panic attack. A panic attack is a sudden episode of intense fear that is accompanied by physical symptoms such as a racing heart, rapid breathing, and clammy hands. It is a common symptom of panic disorder, which is an anxiety disorder.