The smallest or weakest animal in a litter of babies, or an insulting term for a small or insignificant person.
From Middle English, possibly from Old Norse 'runti' (a small and stunted animal). The term has been used since at least the 16th century with similar meaning.
In animal biology, runts are often not smaller because of genetics—they're smaller because they ate less in the womb, which is why hand-raising them can make them thrive, showing that 'runt' describes circumstance, not destiny.
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