Hackle is a noun that refers to the hair along the back of the neck that rises when a person is angry. 

Coming from Late Middle English, our word of the day is frequently used in reference to dogs that are not in a great mood. Here’s an example:

Like many Dobermans, Roscoe’s hackles get raised when he hears weird noises at the front door. After all these years of being around him, I find the hairs on my back standing up too when someone is a little too loud at the door.