In Australian English slang, the expression "to arc up" means "to become upset or angry" (Wikitionary), e.g. "he arced up at his boss after being denied a promised pay rise", or "it was just a joke, no need to arc up."
I am struggling to verify the etymology of this phrase. It seems opinions are divided: one camp imagines the expression to refer to an electrical arc as in welding or between two live wires held close, the other imagines an angry cat arching its back to look threatening.
One source writes:
I first heard this in Alice Springs in 1996. It was said to mean "losing your temper" or "getting defensive"... I think it might be related to the arch in a cat's back used to ward off an offending approacher.
While another says:
I think it comes from steel welders starting to weld so look away.
I had thought the etymology was evidently the electrical explanation, but I find the feline framing fitting, if fanciful. Trouble is, I have no idea how to even approach the problem of discovering its roots. To an extent, both are automatically "valid" if enough people subscribe to them, but it seems plausible that people were saying it and thinking about cats long before the idea of an electrical arc was part of the vernacular.
Any ideas on how to pin this one down?