Get your back up
Meaning
To become suddenly defensive, angry, or ready to argue when feeling challenged or threatened.
Origin
Picture a cat, startled by a sudden noise or confronting a rival. Its hackles rise, its fur bristles, and its back arches into a formidable curve. This physical display, making the animal appear larger and more menacing, is a universal signal of defensiveness and readiness to fight. Humans, keen observers of the natural world, adopted this vivid image in the 19th century. To 'get your back up' became a metaphor for that same instinctive, bristling reaction in people – not a physical arching of the spine, but an immediate emotional hardening, a defensive stance taken when feeling threatened or challenged, ready to lash out.
Examples
- When her boss criticized her project, she immediately got her back up and started arguing.
- Don't mention his old rival; he'll get his back up for sure if you bring up that topic.