get someone’s back up, to

To make someone angry. The expression alludes to the behavior of the domestic cat, which arches its back when it is attacked by a dog or is otherwise annoyed. This term began in the early eighteenth century as to put or set up the back. By 1864 it was, “He goes his own way . . . if you put his back up” (Sunday Magazine). See also GET SOME- ONE’S DANDER UP.