Meanings
- idiomaticOne is offended or angry.
Now my back is up. “Yes, the witch,” I hiss.
2014, Kristin Butcher, Cabin Girl, →ISBN2 more examples
My back is up, and I cannot hear the thought of wooing him any farther, nor would do it, though he were as pig a gentleman (look you) as Lucifer himself.
1835, William Hayley, The Life and Letters of William CowperAnd I want you to be nice to Patty. For some reason her back is up.
2011, Jeannie Watt, The Baby Truce, →ISBN, page 84
Origin
From the way a cat, when angry, raises or arches its back.
Full word history & related roots →Cite this entry
one's back is up. (n.d.). In WatkinsX Dictionary. Retrieved November 5, 2026, from https://dictionary.watkinsx.com/word/one's%20back%20is%20up
“one's back is up.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/one's%20back%20is%20up. Accessed November 5, 2026.
WatkinsX Dictionary, s.v. “one's back is up,” accessed November 5, 2026, https://dictionary.watkinsx.com/word/one's%20back%20is%20up.
Source: one's back is up on Wiktionary, CC BY-SA 4.0.