A conniption is a sudden, violent emotional outburst or fit generally triggered by shocking news or an unexpected turn of events. This is typically a slang or informal term, with American origins though the exact source of the phrase is unknown. It can be used with other expressions like "hissy fit" or "tantrum," though there are subtle differences between each of these outbursts.
Unlike a tantrum, which could be triggered with little outside provocation, a conniption is often an anticipated response to incredibly bad or disappointing news. For example, someone who is already running late for an important meeting, and then encounters a road block on the way to it, may go into "conniptions." It is generally characterized by a tirade of strong language accompanied by signs of frustration, rage, and even sadness. Sometimes a person having a conniption is reduced to stutters and incomprehensible sounds or phrases.
Usage and Differences from Similar Terms
Some people use "conniption" interchangeably with other descriptors such as "temper tantrum" or "hissy fit." While each phrase can describe a violent emotional outburst, there are some subtle differences. An emotionally immature person experiencing frustration or disappointment is likely to have a temper tantrum. For example, a child who drops an ice cream cone might have such a tantrum.
A person with a histrionic personality or poor anger management skills might have a hissy fit when faced with disappointment or denial, a response generally seen as immature or inappropriate for the situation. In contrast to this, however, a conniption could be triggered whenever an otherwise rational person is confronted with an irrational set of circumstances. Under such conditions, an emotional response may very well be anticipated, although many people see a conniption as an inappropriate momentary lapse of reason regardless of the cause.
Source for "Conniption"
The origins of the term "conniption" are not exactly clear, although many sources place the first known usage around the 1830s. Some people theorize the word "conniption" is literally a corruption of the word "corruption," which at one time described feelings of anger or sadness. Others believe the word "conniption" was formed as a nonsense word, suggesting a mock Latin origin, or reflecting the types of sounds that might be voiced during such a fit.
There was also an informal English word, canapsha, which had roughly the same meaning as "conniption" in the early 19th century. It is even possible that the phrase "conniption" arose from the Yiddish language. Yiddish words like knish are routinely pronounced with both the hard "K" and "N" sounds, in much the same way as "conniption."