get someone's back up

get (one's) back up

To become or cause to become angry, hostile, defensive, or irritable. John got his back up when his parents brought up the subject of college. Election season always gets my dad's back up.
See also: back, get, up

get someone's back up

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.
See also: back, get, up

get someone's back up

INFORMAL or

put someone's back up

BRITISH, INFORMAL
If someone or something gets your back up or puts your back up, they annoy you. What does get my back up is a girlfriend who gets jealous if someone else finds me attractive. I thought before I spoke again. The wrong question was going to get her back up. The appointment took the whole office by surprise and at first seemed to put people's backs up. Note: This expression may refer to the way cats raise their backs when they are angry.
See also: back, get, up