The phrase "make hair stand on end" is an idiomatic expression used to convey a strong feeling of fear, shock, or intense emotion that causes one's hair to stand upright. This phrase is derived from a physiological response known as "piloerection," where tiny muscles at the base of hair follicles contract, resulting in the hair standing on end.
Metaphorically, when something or someone "makes hair stand on end," it implies that they elicit such a profound emotional reaction that it causes a sensation akin to the physical response of hair standing upright. This expression is often used to depict an extreme sense of horror, terror, or distress, which generates a feeling of discomfort or uneasiness in the affected person.
The phrase can be employed in various contexts, such as describing a chilling or spine-tingling experience, a terrifying story, a shocking revelation, or an intense thrill. It suggests that the subject matter is so alarming or unsettling that it has a powerful impact on one's emotions, leaving them in a state of heightened awareness or fear.
In summary, to "make hair stand on end" denotes an intense and disturbing emotional reaction that causes a person's hair to stand upright, typically used to describe a frightening or shocking experience that generates a profound sense of fear, terror, or distress.
