Definitions:

1. The long, narrow feathers on the neck of a bird, such as a domestic rooster, which can be raised during displays of aggression or alarm. NOUN
   • The rooster's hackles flared as it confronted another bird.
2. The stiff, erect hairs along the neck and back of an animal, especially a dog or car, which stand up when the animal is agitated, frightened, or angry. NOUN
   • The cat's hackles were raised when it encountered a barking dog, indicating it was scared or defensive.
3. Used metaphorically to refer to a person's feeling of anger or irritation. ADJECTIVE
   • The condescending tone of his remarks raised her hackles.

Synonyms:

• bristles
• Erect hairs
• feathers
• quills