prettygoodword | hackles

hackles (HAK-ulz) - pl.n., the feathers on the nape of a bird, such as a rooster, that can be raised in a threat or dominance display; by extension, the hairs on the nape of a mammal, such as a dog, that can be raised when frightened or angry; by extension, any anger or defensiveness.

The Official Usage Forms are"raise (someone's) hackles," which is usually a transitive action, and "get (one's) hackles up," which is intransitive. There are, btw, other additional meanings, such as a device used to comb out long fibers of flax, hemp, or jute (this meaning dates to the 15th century, from its tine's resemblance to the rooster feathers), a feather used in a fishing lure (17th century), and a feather plume on a military headdress (I'm not finding a date). The hairs on a dog is 19th century, and was almost immediately followed by the figurative extension in humans. The feather meaning (also dating to the 15th century) is from Middle English hakell/hakle, cloak/skin/plumage, from Old English hacele, cloak/mantle, from Germanic roots. The yellow feathers on this rooster are the hackles: