With regard to some significations, approved terminology, and the like:

While there may be some connection between the Scots "carnaptious" (various spellings and indeed pronunciations) and the North American "conniptions", the two words are not synonyms. The American word seems to provide a humorous way of saying "he must have had a fit", though perhaps that expression is now discountenanced because of associations with symptoms of various diseases; how about, "he must have had kittens", "he nearly had a canary", both of which are nonsensical but widely understood and, as far as I can see, do not allow anyone to seize the opportunity to claim that they find the terms offensive.

The Scots word, "curnaptious" (yes, there are various pronunciations) conveys quite a different meaning, though it's possible to suggest a connection with or influence upon the American word. For a start, it's an adjective, as Backwoodsman's post of 16th June, 07.19 AM, shows. A person not just disposed to argue, but in a constant state of irritation, sudden and quick in quarrelling, girnan like a crabbit wee dug and aye barin' the teeth at ye like a Celebrity wi' a flick tae brag, could appropriately be described as "curnaptious", but he might just hanch at ye, more because it's his nature than to suggest an etymology.

On another tack, while the term "Native American" might have been well intentioned, it's not surprising that there's not anything like agreement on its adoption; why should people who can trace their traditions back for thousands of years consent to accepting the name of some comparatively recent Italian explorer? In the 1960s, a term I know to have been used among some tribes was simply, "The Red Man", though I think the current position is to favour "First Nations".

ABCD.