Hackles

Part of speech: noun

Pronunciation: /ˈhækəlz/

Definitions

1. The elongated hairs along the back of certain animals that rise in response to fear or aggression
2. The raised fur or hair along an animal's back, indicating a defensive or threatening posture
3. A state of heightened alertness in animals, shown by the bristling of fur along the neck and spine

Etymology: The term originally referred to the long, stiff hairs found along the back and neck of certain animals, especially dogs and horses. These hairs, called "hackles," would often rise or stand erect when the animal was alarmed or angry, signaling a state of heightened alertness or aggression. This physical reaction captured human attention and became a vivid metaphor for a similar feeling of tension or indignation in people. The use of the word in English dates back to the 16th century, when it was borrowed from the Middle English "hakel," which itself comes from Old English "hæcel," meaning a kind of comb or tool for dressing flax. This connection to a comb is important, as the stiff hairs resembled the bristles of such tools. Over time, the meaning shifted from the physical object to the anatomical feature on animals. By the 17th century, the word began to be used figuratively to describe a person’s emotional state—especially a sense of anger or irritation that causes one’s "hackles" to rise, much like the animal’s hairs. This metaphorical extension captures the idea of a prickly, defensive response to provocation. It remains a popular expression in English, often used to describe a sudden, instinctive feeling of offense or unease. Thus, the journey of the word moves from a simple tool for combing fibers, to the literal hairs on an animal’s neck, and finally to a vivid image of human emotional defense. This layered evolution preserves the tactile and visual impressions that give the term its emotional punch.

Synonyms: bristles, spines