Definition
Hackles are the hairs on the back of the neck that stand up when an animal (or a person) is scared or angry. When someone says, "Their hackles rose," it means they became defensive, agitated, or aggressive. Think of a dog baring its teeth and raising its fur. 🐶 It signifies a readiness to fight or flee. It's a primal, instinctual response. Imagine someone suddenly feeling threatened; their hackles would rise.