This idiom describes someone who suddenly loses their temper or becomes extremely angry, often in an impulsive or uncontrolled manner. It evokes the image of an axe head flying off its handle during a swing, suggesting a dangerous or unexpected outburst. The phrase is used in personal, social, or workplace contexts to highlight emotional volatility, carrying a critical or cautionary tone. It reflects cultural associations of anger with unpredictability and the need for self-control, often implying that such reactions are disproportionate or disruptive.

The phrase originated in 19th-century America, rooted in rural life where poorly maintained tools, like axes, could have loose heads that flew off during use, posing danger. An early use appears in Thomas Haliburton’s 1843 *The Attaché*: ‘He flies off the handle at the least thing.’ The idiom gained traction during the American frontier era, reflecting a rugged, tool-based culture, and was popularized by Mark Twain’s *Huckleberry Finn* (1884). Its use grew in the 20th century, particularly in American English, and spread to British English through literature and film. The phrase’s vivid imagery and relevance to emotional outbursts ensured its enduring use, especially in contexts of conflict or frustration.