There was a time in American English when words were like contraptions you could jerry-rig: a bit from here, a bit from there, all bolted together to make a pseudo-classical bit of hickery. Absquatulate and copacetic are two classics – though copacetic is the newer by nearly a century, showing up circa 1910. Absquatulate hit the scene around 1830. So did contraption – a pseudo-classical construction with a trap stuck in it. And so did conniption.
You know what a conniption is, right? It’s a fit: a fainting fit or a hissy fit or some other pique or fright. We often see the redundant (but assonant) phrase conniption fit – in fact, that’s how it shows up in the earliest attested uses.
I think conniption has a good sound; that nip in the middle is fittingly indignant but short; the gathering con could call on confound and condemn and consarn (a fake-swear probably based on concern and usable where one might use goshdarn), and the ption ending brings out not only contraption but corruption, consumption, and conscription – and eruption and exception, among others. And just maybe, the word as a whole has an air of a sneezing fit.
So where did conniption come from? Um, the US… around 1830… and no one’s really sure of anything more than that. There’s speculation, of course, but not even a whole lot of that. It was confected; it fit well; it stuck. If you look at Google ngrams, you’ll see ebbs and flows over the decades.
Mind you, you’ll also see results from the earliest 1800s. Have a look and you’ll find hits like these:
“there are a thousand occasions in which it breaks through its original conniption” —1803
“The economy of injustice is, to furnish resources for the fund of conniption” —1807
“who would be the avengers, not the abettors of conniption” —1811
“the moral conniption of our first parent has been entailed on his whole posterity” —1811
This is rather entertaining. But if you click through and look at the actual photo facsimile, you will find what you may have already guessed: it’s due to bad optical character recognition. This conniption is in every case a corruption… of corruption.
Tsk. It’s enough to give one a conniption.