dander

To become annoyed or angry. Don't get your dander up with me—I'm just trying have a conversation here. I know I got my dander up a bit last night, so I understand why you're avoiding me.

Fig. to make someone get angry. (Fixed order.) Now, don't get your dander up. Calm down. I insulted him and really got his hackles up. Bob had his Irish up all day yesterday. I don't know what was wrong. Now, now, don't get your back up. I didn't mean any harm.

Also, get someone's dander up; put or set someone's back up . Make angry, as in Bill's arrogance really got my back up, or The foolish delays at the bank only put her back up. Get one's back up and get one's dander up mean "become angry," as in Martha is quick to get her dander up. The back in these phrases alludes to a cat arching its back when annoyed, and put and set were the earliest verbs used in this idiom, dating from the 1700s; get is more often heard today. The origin of dander, used since the early 1800s, is disputed; a likely theory is that it comes from the Dutch donder, for "thunder." Also see get someone's goat; raise one's hackles.

To be angry. “Dander” is the particles of hair that break off an animal's hair (humans call it “dandruff” when it happens to us). “To get your dander up” calls to mind the hair that stands up on the nape of an enraged dog's neck. Another meaning of the word is the ferment used in making molasses; getting your dander up in that context suggests that your anger is rising the way yeast or any other leavening or fermenting agent does.