Until a couple of days ago, as a British English speaker, it had never occurred to me that someone might use the word careen as a verb meaning to move swiftly and often rather recklessly. For that, I’d use the word career. It turns out to be a difference in usage between American and British English, which has developed relatively recently.

The verb career, a verbalisation from the noun, originally came to mean to take a short gallop, to ‘pass a career’, that is a short gallop at full pelt. The Oxford English Dictionary dates that use as far back as 1594, although even then it was also being used figuratively. Its meaning continued to drift (rather than career), to mean to gallop or move at full speed, with an element of recklessness starting to move in. Then by the nineteenth century, English writers were starting to refer to clouds and even people careering.

These all ultimately derive from the French carrière, a racecourse, and the late Latin carraria, a carriage-road.

Careen has an equally long history, starting from the Latin carina, meaning the keel of a boat or ship. By 1600 it was being used as a verb, for the action of turning a vessel onto one side so that its keel and hull could be cleaned and repaired. Then in the 1920s, American English started to use careen to mean to rush headlong or hurtle, particularly in an unsteady manner. People, thoughts, even tears came to be described as careening.

One of the earliest occasions for this novel usage is in Edgar Rice Burroughs’ Chessmen of Mars, a fantasy novel published in 1921-22, where he wrote:
The cruiser ‘Vanator’ careened through the tempest.

This is an unusual situation where he could easily have been punning with the word, given that he was writing about a cruiser, albeit an aerial vessel.

One interesting way to look at the changing history of the usage of these words is using the Google Ngram Viewer. This plots the frequency of occurrence of words or combinations in Google Books over time.

Inevitably, this does not look at the meaning of words. As both careen and career have other uses and meanings, we need to find a form or combination of words which picks out our intended meaning better. In this case, the words careening and careering are more likely to apply to our intended usage, although there will still be circumstances in which they could refer to the action of turning a vessel on its side or of galloping.

Limiting the search to British English books between 1800 and 2008, careening was initially very infrequent, and became even less common. It enjoyed a small peak around 1975, but remains little-used.

In American English books over the same period, careening suffered a slow decline until the early 1920s, since when it has become considerably more frequent, and by 2008 was roughly four times more common than it was over the period 1840-1920.

This is consistent with careening being introduced with a new usage pattern, because of a change in its meaning, in American English after 1920.

The final question, though, is how did a word derived from the keel of a boat/ship come to be associated with rushing headlong in an unsteady manner? My bet is that it acquired that meaning by mistake. Being very similar to career, the word careen became inadvertently substituted for it. British English usage has apparently resisted that, so far.