Acting quickly without thinking carefully about consequences; in a hasty or reckless way.
From 'rash' (from Middle English, possibly from Old Norse 'roskr' meaning quick or brisk, or German 'rasch') plus -ly. The meaning evolved from 'quick' to 'quick without judgment' over time.
Your brain's amygdala (fear center) can make you act rashly in seconds, but your prefrontal cortex (judgment) takes 20+ minutes to fully engage—which is why the 'pause before reacting' advice actually has hard neuroscience behind it!
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