impetuous

A Roman could have heard impetus in a battlefield report and pictured cavalry thundering forward, dust flying, no time for second thoughts. That same word later slid into Late Latin as impetuosus, then into French as impétueux, where it kept the sense of something that surges before it thinks. By the late 1300s, English borrowed it for a person whose emotions charge ahead like a horse that has spotted an open gate. It belongs to the same little family as impetus, that lovely noun for the shove behind a machine, an argument, or a career. Say someone is impetuous, and you are really saying their judgment got left behind somewhere near the starting line.